Cook onions in 1 tablespoon of butter for about 2 minutes on medium heat.
Add pierogies to onions and cook, flipping occasionally for 8 minutes or until crisp on both sides. Set aside.
Cook bacon in separate pan or in microwave at the same time. I cook it in the microwave with paper towels to soak up the extra grease. Set aside.
Butter the bread with the leftover butter while the pierogies are cooking.
Place one piece of bread, butter side down, on pan. Do not turn the stove back on yet.
Stack the rest of the ingredients on the bread. American cheese, pierogies with onions, paprika, pepper, bacon, cheddar cheese, and the last slice of bread, butter side up.
Turn on stove top to medium heat. Cook one side of sandwich for five minutes or until cheese on bottom is slightly melted.
Carefully flip the sandwich. Two spatulas didn't hurt!
Cook other side of sandwich for another few minutes. Continue cooking/ flipping until desired darkness of bread. Move to plate or cutting board.
Wait a couple minutes and cut if preferred. Add sour cream to plate for dipping. Enjoy!
