Bring a large pot of water to a boil. Boil pierogi and stir occasionally for five minutes. Drain and place in a bowl.
In a skillet, heat up the olive oil, add garlic and mushrooms and cook for about five minutes (until the mushrooms release their water).
Add white wine and cook for another three minutes.
Whisk in flour and cook for a minute or two.
Add chicken broth stirring constantly until the sauce thickens.
Add in the parsley, salt and pepper to taste.
Toss in pierogi.