Preheat your oven to 375°F (190°C) and take a moment to properly grease an 8×8-inch baking dish with oil, butter, or nonstick spray. Make sure the sides are well-coated so the quiche releases cleanly after baking. Set the dish aside while you prepare the filling.

Crack the eggs into a large mixing bowl and add the cottage cheese. Using a whisk, immersion blender, or regular blender, blend the mixture until completely smooth and creamy. This step is important for a custard-like texture—blending removes cottage cheese curds and helps the quiche bake evenly without a grainy feel.

Add your seasonings to the egg mixture, such as salt, black pepper, garlic powder, onion powder, or dried herbs. If using milk or yogurt for extra creaminess, stir it in now. Whisk gently until everything is fully incorporated and the mixture looks uniform and slightly frothy.

If your spinach is fresh, chop it finely; if using frozen spinach, make sure it is fully thawed and squeezed very dry to remove excess moisture. Fold the spinach into the egg mixture along with any optional shredded cheese, using a spatula to distribute everything evenly without overmixing.

Pour the prepared mixture into the greased baking dish. Use a spatula or the back of a spoon to smooth the top so the spinach and cheese are evenly spread, which helps the quiche bake uniformly and look neat once finished.

Place the dish on the center rack of the oven and bake until the quiche is set in the middle and lightly golden on top. This usually takes about 30–40 minutes. The center should no longer jiggle when gently shaken, and a knife inserted should come out mostly clean.

Remove the quiche from the oven and let it rest for 10–15 minutes before slicing. This resting time allows the proteins to set fully, making the quiche easier to cut into clean slices while improving texture and flavor.