Preheat oven to 350 degrees F.
Place the potatoes in a large pot with water to cover over medium-high heat. Bring to a boil and cook until the potatoes are tender; remove from heat, drain, then combine with the milk and butter. Mash and set aside.
In a large skillet over medium-high heat, saute the bacon and onion for 10-15 minutes, or until the bacon is fully cooked. Add garlic and cook for 1 minute more.
Cook the lasagna noodles according to package directions and cool under running water.
Place a third of the mashed potatoes into the bottom of a 9x13 inch baking dish. Top this with 1/4 of the cheese, followed by a layer of lasagna noodles. Repeat this twice with the potatoes, cheese and noodles.
Then arrange the bacon, onion and garlic over the noodles, then another layer of noodles, and finally top all with the remaining cheese. Season with salt and pepper to taste.
Bake, uncovered for 30-45 minutes, or until the cheese is melted and bubbly.
Serve with sour cream and chopped fresh chives.