Almost Instant Pierogis - cooking recipe

Ingredients

3 lb. (8) potatoes
6 c. sliced yellow onions
2 c. (8 oz.) shredded cheese (Cheddar or Colby)
1 (16 oz.) box jumbo shells, cooked firm
1 Tbsp. salt (optional)
1/2 c. margarine

Preparation

Drain and cool shells immediately under cold water.
Cool and drain cooked potatoes.
Add cheese to potatoes.
Mash; add salt and pepper to taste.
Melt butter and add onions; cook until tender.
Spread 1/2 onions equally over 2 (9 x 13-inch) baking dishes.
Gently stuff each shell with heaping tablespoon of potato mixture.
Bring sides of shells together over filling.
Arrange in single layer on onions.
Spread remaining onions on top.
Bake, uncovered, in preheated oven at 350\u00b0 for 15 to 20 minutes.