- Southwest Sauce:
- 1/2 cup sour cream
- 1/4 cup ranch dressing
- 1/4 cup taco sauce
- 4 (4 ounce) hamburger patties
- 1 dash Worcestershire sauce, or to taste
- 8 flour tortillas
- 2 cups shredded sharp Cheddar cheese
- 2 cups shredded Colby-Jack cheese
- 1/2 head lettuce, shredded, or to taste
- 3 tablespoons picante sauce, or to taste
- Mix sour cream, ranch dressing, and taco sauce together in a bowl until Southwest sauce is smooth. Cover bowl and refrigerate for flavors to blend.
- Preheat an outdoor grill for medium-high heat and lightly oil the grate.
- Cook hamburger patties in the preheated grill for 5 minutes, seasoning with Worcestershire sauce. Flip patties. Arrange tortillas on the grill and lower heat to medium-low under tortillas. Add Cheddar cheese and Colby-Jack cheese to tortillas; cook until cheeses melt, 2 to 4 minutes. Continue cooking hamburger patties until cooked through, about 5 minutes more. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).
- Spread Southwest sauce onto 1/2 of the tortillas; top with lettuce and picante sauce. Place 1 hamburger patty on top of picante sauce layer and top patty with a tortilla, creating a sandwich.