Preheat your oven to 375°F (190°C) to ensure even cooking.
Heat 1 tablespoon of olive oil in an oven-safe skillet over medium heat. Add minced garlic and chopped onion; sauté for 2-3 minutes until translucent.
Add chopped red and green bell peppers and broccoli florets. Cook for 3-4 minutes, stirring occasionally, until vegetables soften.
Stir in shredded zucchini and chopped sun-dried tomatoes. Cook for another 2 minutes to meld flavors.
In a mixing bowl, whisk together eggs, almond milk, grated Parmesan cheese, dried oregano, red pepper flakes, black pepper, and a pinch of sea salt until well combined.
Pour the egg mixture over the sautéed vegetables in the skillet. Gently stir to combine evenly.
Cook the frittata on the stovetop for about 5 minutes until the edges start to set.
Transfer the skillet to the preheated oven and bake for 15-20 minutes until puffed and the center is set.
Remove from oven, let cool a few minutes, slice into wedges, and serve warm.