Blackstone Sausage and Pierogies

Name: Blackstone Sausage and Pierogies
Prep time: 10 min
Cook time: 15 min
Total time: 25 min
Cuisine: American
Ingredients: 1 16 ounce box frozen pierogies (thawed but not cooked); cooking oil of choice; 1 onion (diced); 1 red bell pepper (sliced); 1 yellow bell pepper (sliced); 1 pound smoked sausage (sliced); kosher salt, pepper, crushed red pepper flakes; 8 ounces fresh chopped spinach; 5 to 6 cloves garlic (minced); 1 16 ounce jar alfredo sauce; 1/2 cup shredded parmesan cheese