Place pierogies, onion, red pepper, bacon, salt and pepper in a large freezer bag.
Add the cream of mushroom soup and evaporated milk to a bowl. Whisk together the two ingredients until well combined.
Pour the sauce over the other ingredients in the freezer bag. Squish the bag to combine the sauce and other ingredients. Remove excess air from the bag and seal it.
Put the shredded cheese in medium freezer bag and seal.
Staple the bag of cheese to large bag above the seal and place in the freezer.
Oven Cooking Instructions:
Thaw.
Preheat the oven to 350° and grease a casserole dish with nonstick cooking spray.
Dump the ingredients in the larger freezer bag into the casserole dish. Top with the shredded cheese.
Bake the casserole for 45 minutes, until the sauce is bubbly and the cheese on top is melted.
Slow Cooker Instructions:
Thaw.
Dump large bag into slow cooker. Top with the cheese.
Cook on low for 4 hours or on high for 3 hours.
Notes
Easily make this vegetarian by omitting the bacon or substituting with imitation bacon bits.