SWEET POTATOES: Preheat oven to 400°F or 200°C. Peel the sweet potatoes and chop them into small bite-size pieces.Transfer to a baking tray and season with 1½ tablespoons olive oil, ½ teaspoon salt, and 2 teaspoons taco seasoning.Toss, arrange in a single layer, and bake for about 30 minutes or until fork-tender and slightly charred.
SAUTÉED CORN: Slice the corn kernels off the cob.Heat 1½ tablespoons olive oil on a skillet, add the corn, and season with ½ teaspoon salt and 2 teaspoons taco seasoning.Sauté on medium heat for 5 minutes or until the corn softens and gets slightly charred.
ASSEMBLE THE TOSTADAS: We recommend starting with a layer of refried beans. This helps the other toppings stay glued to the shell.SWEET POTATO TOSTADA: Refried beans, sliced avocado, pico de gallo, roasted sweet potato, sour cream, salsa verde, and sliced red cabbage.SAUTÉED CORN TOSTADA: Refried beans, sliced avocado, pico de gallo, sautéed corn, crumbled queso fresco or crumbled feta, hot sauce, and sliced lettuce.
Nutrition information is an estimate for 1 tostada out of 16. I would serve 3 to 4 tostadas per person as a main meal.SUBSTITUTIONSCorn tostada shells: Substitute taco shells.Refried beans: substitute white bean dip, lentil hummus, and avocado spread.Pico de Gallo: substitute store-bought Mexican salsa.Salsa Verde: substitute tabasco hot sauce or sriracha.Iceberg lettuce: substitute thinly sliced Romaine lettuce.Red cabbage: substitute green cabbage.Corn: Substitute red bell pepper and chop it into small dice.Sweet potatoes: substitute cauliflower, cut it into small florets, and roast it the same way.Sour cream: substitute unsweetened yogurt.Queso fresco: substitute crumbled feta cheese.Vegan: to make the recipe vegan, you can substitute the sour cream for vegan sour cream and the queso fresco with non-dairy feta or vegan cheese.STORAGEMake ahead: You can prepare the toppings ahead of time and keep them in separate bowls covered with plastic wrap in the refrigerator for several days.Avoid storing assembled tostadas: the corn tortillas get soggy shortly after they are topped.