Boil the pierogi according to package directions. It typically is 8-10 minutes in 2 quarts of boiling water. Once they are cooked, drain in a strainer.
2 boxes Mrs. T's Classic Pierogies
In another pot, melt 4 tablespoons of butter. Add diced ham and cook for 2 minutes. Add 2 tablespoons of flour.
8 ounces diced ham, 4 tablespoon butter, 2 tablespoon flour
Add 1 cup milk to the pot and let it simmer for 3 minutes.
1 cup whole milk
Add half the package of cheese to the sauce. Cook for about 3-4 minutes or until thickened. Season with pepper.
8 ounces sharp cheddar cheese, black pepper
Combine the cooked pierogi with the ham and cheese sauce.
Add to a 9x13 greased baking dish. Top with remaining cheese.
Bake at 350 degrees for 20 minutes.