Place a large skillet over medium heat and add the ground protein. Cook it slowly, breaking it apart with a spatula or wooden spoon as it browns. Continue cooking until the meat is fully cooked through and any excess moisture has evaporated, as this step helps prevent the casserole from becoming watery later.

Add the diced onion, chopped bell peppers, and minced garlic directly to the skillet with the cooked protein. Stir everything together and cook for several minutes, until the vegetables soften, release their aroma, and blend naturally with the meat.

Sprinkle the taco seasoning evenly over the mixture and stir thoroughly so the spices coat the protein and vegetables completely. Let it cook for another minute or two to allow the flavors to bloom and deepen.

Reduce the heat slightly to prevent the dairy from overheating, then gently stir in the cottage cheese or Greek yogurt. Mix slowly until the mixture becomes creamy and evenly combined, taking care not to overmix or let it simmer aggressively.

Transfer the mixture into a lightly greased baking dish and use a spatula to spread it into an even layer. Smoothing the surface helps the casserole bake evenly and ensures consistent texture in every serving.

Sprinkle the shredded cheese evenly across the top of the casserole, covering the surface so each portion gets a balanced amount of melted cheese.

Place the baking dish into a fully preheated oven and bake until the casserole is heated through and the cheese on top is fully melted and lightly golden, without becoming overly browned.

Remove the dish from the oven and let it rest for a few minutes before serving. This short resting time allows the casserole to set slightly, making it easier to slice and serve neatly.