Preheat your oven to 375°F (190°C) and generously spray a standard 12-cup muffin tin with non-stick cooking spray to prevent sticking.
Warm the small flour tortillas slightly in the microwave, then press each one gently into a muffin cup to form a bowl shape. Trim if needed.
In a large non-stick skillet over medium-high heat, brown the ground beef completely. Add chopped onions, taco seasoning, cumin, garlic powder, and chili powder. Stir and cook until well combined and fragrant.
Spoon a layer of the seasoned meat mixture into each tortilla shell, then top with shredded cheese, a spoonful of salsa verde, and any optional fillings like black beans or corn. Add another light sprinkle of cheese on top.
Bake the taco cupcakes for 12–15 minutes, or until the cheese is bubbling and the tortilla edges are golden brown and slightly crisp.
Let the cupcakes cool for 3 minutes in the pan before removing. Garnish with sour cream, diced tomatoes, chopped cilantro, and sliced green onions. Serve immediately while warm.
