Created by KittenCal on August 7, 2011
Step 1: Preheat oven to 350 degrees F (set oven rack to bottom position).
Step 2: Grease a 13 x 9-inch baking dish.
Step 3: In a large bowl whisk the mayonnaise with sour cream, melted butter, garlic powder, salt and black pepper until smooth and thoroughly combined.
Step 4: Mix in green and yellow onion and 1 1/2 cups shredded cheddar cheese (you may increase to 2 cups shredded cheese if desired).
Step 5: Using a spatula gently mix in the cubed potatoes and cooked chopped bacon (at this point you may cover and refrigerate for up to 2 days).
Step 6: Bake in a preheated oven for about 40 minutes.
Step 7: Immediately after baking sprinkle 1 cup shredded cheddar cheese on top and allow to melt.