To prepare a tortilla de patatas recipe, you first need to prepare the filling for the tortilla. To do this, first you'll need the following ingredients: 12 cup (120 g) sour cream 1 tablespoon (25 ml) mayonnaise 2 tablespoons (60 milliliters) salt 1 tbsp. paprika (optional) 1 teaspoon (2.5 grams) cayenne pepper