Preheat oven to 400 degrees F.
Seed the bell pepper and chop into 1” chunks. Peel the onion and chop into chunks, as well. Slice the chicken sausage into coins 1”-2” in length.
1-2 bell peppers, 1 small onion, 4 links chicken sausage
Combine the chopped pepper, onion, and sausage in a medium bowl and toss with 1 Tablespoon olive oil, 1/2 teaspoon salt, and about 1/8 teaspoon black pepper. Spread this mixture out on a large rimmed sheet pan and place in the oven for 5 minutes. (Line the pan with parchment paper for the easiest clean-up.)
2 Tablespoons olive oil, kosher salt and black pepper
While the veggies start roasting, place the mini pierogies, still frozen, in the same bowl. Drizzle with 1 more Tablespoon olive oil plus the mustard, vinegar, another 1/2 teaspoon salt, and another 1/8 teaspoon black pepper. Stir well to coat.
1 box (12.84 ounces) miniature pierogies, 1 Tablespoon whole grain mustard, 1 teaspoon apple cider vinegar
After the veggies have been in for 5 minutes, add pierogies to the sheet pan and return to the oven. Cook for another 18-20 minutes, until pierogies are golden-brown, the pierogies and veggies are tender, and the sausage is hot and crisp on the edges.
Sprinkle with parsley and serve.
parsley