01 -
Heat refried beans in a small saucepan over medium heat, stirring occasionally. Add a small amount of water if needed to achieve a spreadable consistency. Adjust seasoning to taste and keep warm.
02 -
Heat olive oil in a large skillet over medium heat. Add chopped onion and sauté until softened, about 3 minutes.
03 -
Add ground beef to the skillet and cook, breaking it apart with a spatula. Stir in chili powder, cumin, paprika, garlic powder, onion powder, salt, and black pepper. Cook until beef is browned and cooked through, about 4 minutes.
04 -
Incorporate drained diced tomatoes into the beef mixture. Continue to cook, stirring occasionally, until most of the liquid has evaporated, about 5 to 7 minutes.
05 -
Spread a layer of warm refried beans onto each tostada shell. Top with a generous scoop of seasoned beef mixture, followed by shredded cheddar cheese, lettuce, chopped tomatoes, and onion.
06 -
Arrange assembled tostadas on a platter and serve immediately while toppings are fresh.