Preheat the oven to 375°F and grease 8 cups of a standard muffin pan. Warm the tortillas for 15 seconds in the microwave so they become flexible.
Brush both sides of each tortilla with melted butter and coat with the cinnamon sugar. Press the tortillas into the muffin cups, folding the edges as needed to form dessert cups.
Bake for 10 to 12 minutes until crisp and golden. Let the churro cups cool completely in the pan.
Whisk the vanilla pudding mix with the cold milk for 2 minutes. Refrigerate it for 5 minutes to thicken.
Whip the heavy cream, powdered sugar, and vanilla extract to firm peaks. Fold half of the whipped cream into the pudding.
Layer the pudding mixture and banana slices inside the churro cups. Top with the remaining whipped cream and drizzle with dulce de leche.