Potato and Onion Perogies Frozen Japanese Vegetables The best way to cook the perogies is to saute them in a bit of olive oil. Stem the vegetables while the perogies are cooking. When the perogies have a few minutes left to cook throw the vegetables in with them. Now I let the perogies brown a little but so there is a it of a crisp on the top and bottom, but not too much. simple recipe. peace.