• Step 1: Preheat your oven to 400°F (200°C).
• Step 2: In a large skillet, cook the ground beef over medium-high heat, breaking it up as it cooks, until no longer pink, about 5-7 minutes. Drain any excess fat, then stir in the taco seasoning and 2 tablespoons of water. Simmer for 2-3 minutes, or until the sauce has thickened.
• Step 3: Place 4 of the tortillas on a baking sheet and bake for 2-3 minutes, or until lightly golden and crispy. Flip the tortillas and bake for an additional 2-3 minutes.
• Step 4: Spread a layer of refried beans on each of the crisp tortillas, then top with the seasoned ground beef mixture and shredded cheddar cheese.
• Step 5: Bake the assembled Mexican Pizzas for 5-7 minutes, or until the cheese is melted and bubbly.
• Step 6: Remove the Mexican Pizzas from the oven and top with diced tomatoes and onions. Serve immediately, with a dollop of sour cream on each one.