My family love pierogies for Thanksgiving but they are very time intensive. Here's an easy way to have this Polish favorite. Each step can be done ahead of time and kept refrigerated until you are ready for assembly. Warm the potatoes and onion mixtures slightly and pour a small amount of boiling water over the pasta to make everything easier to handle!
Preheat oven to 350 degrees. Saute butter and onion, set aside on low to stay warm
Prepare the instant mashed potatoes by box instructions cutting back on the milk by half, (potatoes will not be creamy and smooth at this point)and cook pasta shells in boiling salted water for 5 minutes until al dente and drain. Rinse the shells with cool water so they do not stick together. Shells will finish cooking in oven.
Shred the colby cheese(placing the block in the freezer for 10-15 mts makes this step easier)and set aside.
Add 1/2 cup sour cream, the shredded colby cheese, the eggs and about 1 cup of the butter/onion saute to the prepared mashed potatoes. Stir until cheese is melted(you may have to warm the mixture in microwave or back on stove top to completely melt the cheese) You now have your creamy smooth filling. (if potatoes get too runny add a few more flakes of instant potatoes)
Place a small amount of butter/onion saute in bottom of 9 x 13 baking dish.Use a small spoon or a large zipper bag to fill the pasta shells. Place the filled shells face up in dish (crowding is OK), pour remainder of butter/onion saute over the shells. Cover and bake for about 40-50 mts until bubbly and heated through. The filled shells can also be stacked up in a slow cooker adding butter/onion saute to each row and cooked on low for 4-6 hours, or high 2-3 hours until hot and bubbly. Enjoy!