Try different flavor variations, like adding a dash of cinnamon or nutmeg along with the sugar. Ice cream would be terrific in place of the yogurt.
Preheat oven to 375 degrees. Lightly brush both sides of tortillas with melted butter and sprinkle both sides with granulated sugar. Lay tortillas over 6 jumbo muffin cups (tortillas will overlap). Bake until tortillas are soft and pliable, 3 minutes. Remove from oven and, with the bottom of a glass, gently press each tortilla into a muffin cup so it folds up and forms a cup shape. Bake until tortillas are crisp and golden at edges, about 12 minutes. Immediately remove tortillas from cups and let cool completely on a wire rack, 15 minutes.
Meanwhile, in a small bowl, whisk together yogurt and 2 tablespoons brown sugar. In another small bowl, toss together fruit, 1 tablespoon brown sugar, and lemon juice. To serve, divide yogurt mixture among cooled tortilla cups and top with fruit.
Use a juice glass or ladle to form the tortilla cups. You can make them a day ahead: Let cool completely and store in an airtight container at room temperature.