01 -
Preheat oven to 375°F (190°C). Coat a 9 x 9 baking dish with nonstick cooking spray and set aside.
02 -
In a large skillet over medium-high heat, sauté the onion and garlic in olive oil until translucent, about 7 to 8 minutes.
03 -
Remove skillet from heat, then stir in the cream of mushroom soup, sour cream, milk, cheddar cheese and bacon until well combined.
04 -
Spread half of the cheese mixture along the bottom of the prepared baking dish. Arrange the pierogies on top, shingling them to fit if necessary.
05 -
Spread the remaining cheese mixture over the top, ensuring all pierogies are coated. Sprinkle the chives evenly over the surface.
06 -
Bake for 30 to 40 minutes until the top is golden brown and the sauce is bubbling around the sides of the dish. Let cool for 4 to 5 minutes before serving.