This casserole is one of those reliable recipes I reach for when I want something honest, savory, and simple to feed a crowd or make breakfasts stretch through the week. It combines savory turkey breakfast sausage, browned mushrooms, tangy feta, and a gently seasoned egg custard—straightforward ingredients, big flavor payoff. It bakes up into a golden-topped, sliceable dish that’s sturdy enough for plates and portable enough for brunches.

I like it because it’s forgiving: you can brown the sausage until it’s nicely caramelized, or pull the bake a little earlier if you prefer a softer set. The feta brings a briny lift that keeps the egg mixture from tasting flat, and the mushrooms add an earthy texture that plays well against the meat. It’s a practical recipe for weekdays, lazy weekends, or when you want to bring something that travels well.

Below you’ll find the ingredients, a clear step-by-step cook method, troubleshooting tips, and options for swaps and make-ahead strategies. Read through the short notes before you start—small details like letting the casserole rest or using a hot skillet will make the difference between okay and excellent.

Ingredients at a Glance

14 oz turkey breakfast sausage links (see note) — the main savory protein; browning creates flavor and texture.
16 oz. sliced mushrooms (see notes) — provide moisture, umami, and a meaty bite to balance the sausage.
2 tsp. olive oil, or more, depending on your pan — for browning sausage and sautéing mushrooms; add more if the pan is dry.
3/4 cup crumbled feta cheese — brings tang and salt; scatter evenly for flavor pockets throughout the casserole.
8 eggs, well beaten — the custard base that binds everything; beat until smooth for an even texture.
2 T cream (see notes) — enriches the eggs for a silkier set; a little goes a long way.
1 tsp. Spike Seasoning (Use any all-purpose seasoning blend that’s good with eggs if you don’t have Spike.) — the primary seasoning; replace with a similar egg-friendly blend if needed.
fresh-ground black pepper to taste — finish seasoning; add to your preference.
Sliced green onions (optional, but good) — bright garnish that adds freshness and a little crunch.

Cook Sausage, Mushrooms, and Feta Baked with Eggs Like This

Preheat oven to 375°F (190°C). Spray a 9″ x 11″ casserole dish with nonstick spray.
Cut each turkey breakfast sausage link into halves or thirds.
Heat about 1 teaspoon of the olive oil in a large nonstick skillet over medium-high heat. Add the sausage pieces and brown lightly on all sides (about 5–7 minutes).
Transfer the browned sausage to the prepared casserole dish.
If the skillet is dry, add the remaining 1 teaspoon olive oil (use more only if needed). Add the sliced mushrooms and cook over medium-high heat, stirring occasionally, until softened and starting to brown (about 5–7 minutes).
Spread the cooked mushrooms evenly over the sausage in the casserole dish. Sprinkle the 3/4 cup crumbled feta cheese over the mushrooms. Add sliced green onions if using.
In a bowl, beat the 8 eggs with the 2 tablespoons cream until combined. Stir in the 1 teaspoon Spike Seasoning and fresh-ground black pepper to taste.
Pour the egg mixture evenly over the ingredients in the casserole dish. Use a fork to gently stir once or twice so the ingredients are evenly distributed, if desired.
Bake in the preheated oven for about 30–36 minutes, until the eggs are set and the top is just beginning to brown. A knife inserted near the center should come out mostly clean.
Let the casserole rest about 5 minutes before serving. Refrigerate leftovers and reheat briefly in the microwave when ready to serve to avoid overcooking the eggs.

Why You’ll Love This Recipe

It’s dependable and straightforward. The method is simple: brown, sauté, assemble, pour, bake. That minimal process yields a layered dish with contrast—crispy browned sausage edges, soft mushrooms, creamy pockets of feta, and a custardy egg center.

It’s versatile. Serve it straight from the oven for brunch, bake it the night before for an easy breakfast to reheat, or cut it into squares for a portable meal. The bold flavors hold up well with leftovers, and the structure makes clean slices for serving. For anyone who appreciates a savory, no-fuss casserole that still tastes composed, this one delivers.

Allergy-Friendly Substitutes

Turkey breakfast sausage — swap for a gluten-free sausage if you need gluten-free options (check labels for fillers).
Mushrooms — if allergic, replace with an equal volume of diced cooked bell pepper or zucchini for texture without the fungus.
Feta cheese — use a dairy-free feta-style crumble if you need a dairy-free option; choose one labeled for cooking.
Eggs — for egg-free diets, try a commercial egg replacer suitable for baking and stovetop (results will differ in texture).
Cream — use a lactose-free cream or a neutral cooking nondairy creamer if dairy is a concern.

Cook’s Kit

9″ x 11″ casserole dish (glass or metal both work).
Large nonstick skillet for browning sausage and mushrooms.
Mixing bowl and fork or whisk for beating the eggs.
Measuring spoons for the olive oil and Spike Seasoning.
Kitchen tongs or a spatula for turning sausage pieces.
Nonstick spray to prevent sticking and for easier cleanup.

Things That Go Wrong

Underbaked or rubbery eggs usually mean the casserole didn’t bake long enough or it was reheated incorrectly. The center should be mostly set with a slight jiggle—the knife test helps: insert a knife near the center and it should come out mostly clean.

Soggy texture can happen if the mushrooms release a lot of liquid and it isn’t cooked off. Be sure to sauté mushrooms until they’re softened and starting to brown so excess moisture evaporates before assembling.

If the top browns too quickly while the middle is still wobbly, tent the pan loosely with foil partway through baking to slow surface browning and let the center finish cooking.

Dietary Customizations

Want to tailor this to specific diets? Here are practical changes that keep the method intact:

Lower sodium: choose a low-sodium sausage and reduce or omit additional seasoning; rely on feta sparingly for saltiness.
Higher protein: stick with the turkey sausage and consider adding an extra egg or two—note this will increase the custard volume and may change bake time slightly.
Vegetarian: use a plant-based breakfast sausage and a dairy or soy-based feta substitute; brown the plant sausage the same way to develop texture.
Gluten-free: confirm your sausage and seasoning blends are labeled gluten-free.

Notes from the Test Kitchen

Texture and timing

Browning the sausage and mushrooms separately yields the best texture. If you skip browning, the casserole will still work, but it won’t have the same depth of flavor or caramelized edges. I prefer to cook the mushrooms until they start to brown; that reduces water and concentrates flavor.

Feta considerations

Feta varies in saltiness. Taste a small bit while planning seasoning: if your feta is very salty, cut back on added seasoning. Crumbling it evenly helps pockets of flavor appear throughout the bake instead of all in one spot.

Resting is important

Let the casserole rest about 5 minutes before slicing. The eggs continue to set and the slices hold together better. Cutting too early can yield a loose or weepy slice.

Make Ahead Like a Pro

Assemble the casserole up through step 8, cover tightly with plastic wrap or foil, and refrigerate for up to 24 hours. When ready to bake, let the dish sit at room temperature for 15–20 minutes while the oven preheats, then bake following step 9; you may need an extra 5–8 minutes if chilled through. This makes it ideal for hosting mornings when you’d rather sleep in than cook.

Leftovers keep well in the fridge for 3–4 days. Reheat individual portions briefly in the microwave—short bursts to warm through without overcooking. Avoid long reheats that can dry the eggs out; a moist, gentle heat preserves texture.

Reader Q&A

Q: Can I use pork sausage instead of turkey?
A: Yes. Pork sausage will add more fat and a richer flavor; brown as directed and reduce any added oil if the pan becomes greasy.
Q: Can I freeze this casserole?
A: You can freeze fully cooled, baked portions wrapped tightly for up to one month. Thaw in the fridge overnight and reheat gently. Freezing whole bakes is possible but may change texture slightly.
Q: My casserole was watery—how do I avoid that?
A: Make sure mushrooms are well browned and that excess pan juices are cooked off before assembling. Also, don’t overcrowd the skillet when sautéing—cook in batches if needed.
Q: Can I add herbs or other vegetables?
A: Yes—additions like spinach or diced peppers work, but cook them first to remove excess moisture and maintain the bake’s structure.

See You at the Table

This Sausage, Mushrooms, and Feta Baked with Eggs is a dependable, flavorful dish that fits many occasions. It’s easy to scale, easy to adapt, and forgiving in technique—one of the reasons I keep the ingredients on hand. If you give it a try, let me know how you tweaked it or what you served alongside. Happy baking, and see you at the table.

Print Recipe Save it for later

Sausage, Mushrooms, and Feta Baked with Eggs

A baked casserole of turkey breakfast sausage, mushrooms, feta, and eggs — simple to assemble and perfect for breakfast or brunch.

Prep Time22

Cook Time42

Total Time1 34

Course: Breakfast

Servings: 4 servings

Ingredients

14 oz turkey breakfast sausage links see note
16 oz. sliced mushrooms see notes
2 tsp. olive oil or more, depending on your pan
3/4 cup crumbled feta cheese
8 eggs well beaten
2 T cream see notes
1 tsp. Spike Seasoning Use any all-purpose seasoning blend that’s good with eggs if you don’t have Spike.
fresh-ground black pepper to taste
Sliced green onions optional, but good

Instructions

Preheat oven to 375°F (190°C). Spray a 9" x 11" casserole dish with nonstick spray.
Cut each turkey breakfast sausage link into halves or thirds.
Heat about 1 teaspoon of the olive oil in a large nonstick skillet over medium-high heat. Add the sausage pieces and brown lightly on all sides (about 5–7 minutes).
Transfer the browned sausage to the prepared casserole dish.
If the skillet is dry, add the remaining 1 teaspoon olive oil (use more only if needed). Add the sliced mushrooms and cook over medium-high heat, stirring occasionally, until softened and starting to brown (about 5–7 minutes).
Spread the cooked mushrooms evenly over the sausage in the casserole dish. Sprinkle the 3/4 cup crumbled feta cheese over the mushrooms. Add sliced green onions if using.
In a bowl, beat the 8 eggs with the 2 tablespoons cream until combined. Stir in the 1 teaspoon Spike Seasoning and fresh-ground black pepper to taste.
Pour the egg mixture evenly over the ingredients in the casserole dish. Use a fork to gently stir once or twice so the ingredients are evenly distributed, if desired.
Bake in the preheated oven for about 30–36 minutes, until the eggs are set and the top is just beginning to brown. A knife inserted near the center should come out mostly clean.
Let the casserole rest about 5 minutes before serving. Refrigerate leftovers and reheat briefly in the microwave when ready to serve to avoid overcooking the eggs.

Equipment

9 x 11-inch casserole dish
nonstick spray
large nonstick skillet
Mixing Bowl
Fork
Oven
Microwave

Notes

10. Let the casserole rest about 5 minutes before serving. Refrigerate leftovers and reheat briefly in the microwave when ready to serve to avoid overcooking the eggs.