Preheat the oven to 375°F (190°C) and position a rack in the center.
Melt the butter in a microwave-safe bowl (about 30–60 seconds) or in a small saucepan over low heat.
Stir the minced garlic, Italian seasoning, sea salt, and black pepper into the melted butter until well combined.
Pat the chicken thighs dry with paper towels and place them in a single layer in the baking dish.
Spoon or brush the garlic butter evenly over the skin of each thigh, coating the full surface.
Bake on the center rack at 375°F for 40 minutes.
Remove the dish, baste the thighs with the pan juices, then increase the oven temperature to 425°F (218°C).
Return the thighs to the oven and bake 5–10 minutes more, until the skin is golden and as crisp as you like; for extra crispness, move the rack higher and broil 3–5 minutes, watching carefully.
Check doneness with a meat thermometer inserted into the thickest part of a thigh; the USDA minimum is 165°F, though thighs are often cooked to about 180°F for texture.
Let the thighs rest a few minutes, then serve with pan juices spooned over if desired.