If using homemade refried beans, prepare them in advance—Instant Pot refried beans are quick and flavorful. If using canned beans, warm them in a saucepan over medium heat with a tablespoon of olive oil. Stir frequently and season with a pinch of salt, garlic powder, or cumin to taste.

While beans warm up, get your other ingredients ready. Shred the cheese, chop the lettuce, make or open the pico de gallo, guacamole, and prepare any optional toppings like sour cream, hot sauce, or chopped cilantro.

Spread a generous spoonful of refried beans over each tostada shell. Leave about ½-inch border around the edges to prevent spilling. Sprinkle each with about a tablespoon of shredded cheddar cheese.

Spoon on pico de gallo and guacamole over the beans and cheese. Add any optional toppings you like such as pickled jalapeños or a drizzle of hot sauce.

Finish each tostada with a handful of shredded lettuce and a dollop of sour cream if desired. Serve immediately while the tostada shells are crisp and the toppings are fresh.