Preheat the oven to 425°F (220°C). Peel and finely dice the sweet potato; transfer to a parchment-lined baking sheet. Peel and slice the plantains; transfer to a second parchment-lined baking sheet. Drizzle one tablespoon of oil over each sheet and season generously with kosher salt. Toss the sweet potatoes and plantains in the oil to coat evenly. Place the sweet potatoes on the bottom rack of the preheated oven and the plantains on the top rack. Bake for 10 minutes, or until the plantains and sweet potatoes begin to brown. Working one sheet at a time, use a spatula to flip over the plantains and sweet potatoes. Bake for another 10 to 15 minutes, until the sweet potatoes are fork-tender and the plantains are golden brown. Remove from the oven and set aside to cool.
Meanwhile, heat the refried beans in a large pan set over medium heat. Stir frequently; once the beans are warm, turn the heat off and cover the pan.
Heat the tostada shells in the microwave according to package instructions.
Spread the refried beans over the tostada shells. Top with the plantains and sweet potatoes. Garnish as desired and serve at once.
Notes
Today’s recipe is sponsored by the wonderful people over at Old El Paso.If you prefer, you may heat the tostada shells in the oven instead of the microwave. Once the sweet potatoes and plantains are finished cooking, turn off the oven. Remove the sweet potatoes and plantains from the baking sheet and transfer to large plates; discard the parchment. Arrange the tostada shells on the baking sheets and place them in the cooling oven for 2 to 3 minutes, until warm and crunchy.To store Sweet Potato Tostadas, keep the roasted sweet potatoes and plantains in an airtight container in the refrigerator for up to 3 days. Refried beans can also be stored separately in a sealed container. Tostada shells should be kept in a cool, dry place.To reheat the sweet potatoes and plantains in the oven at 350°F (175°C) for 10 minutes or until warm. Assemble just before serving for optimal crispness and freshness.