Preheat oven to 375F
If using oven-ready lasagna noodles, soak them in water while you prepare the rest of the ingredients. If using regular noodles, cook them according to package directions.
Cook the bacon in a skillet until fully cooked and then remove to a paper-lined plate.
Add the chopped onion and minced garlic to the bacon fat and cook until the onions are translucent, stirring occasionally.
Stir the cooked onions, garlic, sour cream, 1/2 cup of cheddar cheese and cream cheese into the mashed potatoes. Crumble and add 2 slices of the cooked bacon.
Line or grease your casserole pan and lay down a layer of cooked noodles.
Spread an even layer of the potato mixture over top of the noodles - about 1 1/2 cups.
Add another layer of the lasagna noodles, then the remaining potato mixture, and a final layer of noodles.
Top with the remaining shredded cheese and cover with tinfoil.
Bake for 30 minutes or until the lasagna appears to be cooked through. Remove the tinfoil and crumble the remaining strip of bacon over top of the lasagna.
Cook for an additional 3-5 minutes to get the cheese nicely melted.