Preheat your grill to medium-high heat or preheat your oven to 400°F.
In a large bowl, combine the sliced sausage, frozen perogies, bell peppers, and onion.
Drizzle the olive oil over the mixture and sprinkle with garlic powder, paprika, salt, and pepper. Toss everything together until well coated.
Cut four large pieces of aluminum foil (about 12x12 inches each). Divide the sausage and perogy mixture evenly among the foil pieces.
Fold the edges of the foil to create sealed packets, ensuring there are no openings for steam to escape.
Place the foil packets on the grill or in the oven. Cook for 20-25 minutes, turning halfway through, until the perogies are heated through and the sausage is browned.
Carefully open the packets (watch out for steam) and garnish with fresh parsley before serving.