Preheat the oven to 375°F.

Cut the 3 whole-wheat (8-inch) tortillas into small pieces and set aside.

In a large skillet over medium heat, add 1 pound lean ground turkey. Cook, breaking the meat up with a spoon, until no pink remains.

Add the medium onion, finely chopped, to the skillet and cook until the onion is softened.

Drain any excess liquid or fat from the skillet.

Stir in 12 ounces salsa, 1 teaspoon cumin, 1/4 teaspoon cayenne pepper, 1/2 teaspoon black pepper, and 1/2 teaspoon sea salt. Mix until evenly combined.

Transfer the meat mixture to a 9 x 13 inch casserole pan and spread it into an even layer.

Evenly distribute the tortilla pieces over the meat layer, then sprinkle 1 cup reduced-fat cheddar cheese over the tortillas.

Cover the pan tightly with foil and bake for 30 minutes. Remove the foil and bake an additional 5 minutes, until the cheese is melted and bubbly.

Let the casserole stand a few minutes before serving. Top with diced avocado and diced tomato if desired.