Preheat oven to 375° F
Warm a tablespoon or two of olive oil. Sauté onions, garlic, and mushrooms for 3-5 minutes until the onions are soft.
Add spinach to the pan, cover for a minute or so to let it wilt.
In the meantime lightly beat the eggs and whites with salt and pepper to taste.
In a separate bowl, crumble or cut up the cheese triangles. Mix with the cottage cheese.
Prepare an 8 x 8" baking dish, or a 12" cast-iron skillet. Spread mushroom, spinach, onion mix along the bottom. The layer of cottage cheese and cheese comes next. Pour the eggs mix over the top.
Bake 20-25 minutes or until the eggs are lightly browned.