Arrange the tortillas around the edges of a sheet pan with one tortilla in the center. Spread about ¾ cup sour cream over the tortillas.
Brown the ground beef with taco seasoning and beef broth until fully cooked and the liquid has reduced. Optional: add 1 diced onion and 6 cloves minced garlic.
Layer on the beef, cheddar cheese, tostadas, lettuce, and tomatoes.
Spread the remaining sour cream on another tortilla and place it in the center. Fold the tortillas over the filling to seal everything in, then brush with melted butter.
Place a second baking sheet on top and bake at 420°F for 20 minutes. Remove the top pan and bake another 7 minutes until crispy and golden.
Add all ingredients to a bowl.
Whisk until smooth.
Refrigerate for 15–30 minutes before serving if time allows
