Ingredients 
  
  10 ounces mushrooms, sliced
  1½ cups corn kernels
  2 tablespoons olive oil
  ¼ teaspoon salt
  ¼ teaspoon cumin
  ¼ teaspoon garlic powder
  Vegetable oil for frying
  8 corn tortillas
  1 cup quartered cherry tomatoes
  1 avocado, diced
  ½ cup chopped cilantro leaves
  1 lime, quartered 
 
 Instructions 

1. Preheat an oven to 425 degrees Fahrenheit. Place the mushrooms and corn on a large rimmed baking sheet and drizzle with the olive oil. Sprinkle the salt, cumin and garlic powder over the top, then use a wooden spoon to toss the vegetables and coat with oil. Arrange the vegetables in a single layer on the pan (as best you can). Roast for 15 minutes, stirring once half-way through.
2. Meanwhile, pour about 2 inches of vegetable oil into a large pot and place over medium heat. Once the oil is shimmering, add the tortillas one at a time and fry until golden brown and crispy, about 1½ minutes. Use tongs to carefully transfer the fried tortillas to a paper-towel lined baking sheet.
3. Assemble the tostadas by placing two fried tortillas on a plate, topping with a quarter of the mushroom-corn mixture, and topping with tomatoes, avocado, cilantro, and lime juice. Repeat with remaining tortillas.