Preheat the oven to 375°F (190°C). Grease an 8-inch baking dish thoroughly with butter or olive oil.
Add the cottage cheese to a blender and blend for 20–30 seconds until mostly smooth.
In a large bowl, whisk the eggs until the yolks and whites are fully combined.
Stir the blended cottage cheese into the eggs until evenly incorporated.
Add garlic powder, onion powder, black pepper, salt, parsley, and chives. Stir gently.
Fold in ¼ cup of shredded cheddar and all of the Parmesan. Reserve the remaining cheddar for the top.
If using spinach or bell peppers, make sure they have been sautéed and excess moisture removed before stirring them into the egg mixture.
Pour the mixture evenly into the prepared dish. Sprinkle the remaining ¼ cup cheddar over the top.
Place in the oven and bake for 30–35 minutes. The edges should be puffed and golden, while the center should look set but still slightly moist.
Insert a knife near the center. It should come out mostly clean, with no liquid egg mixture remaining.
Remove from the oven and let the casserole rest for 5–10 minutes.
Cut into four portions and garnish with additional fresh parsley or chives.
