Heat the olive oil in a large skillet over medium-high heat.
Add the sliced onions and bell peppers. Cook for about 5 minutes until they begin to soften.
Stir in the garlic and cook for 30 seconds.
Add the kielbasa and cook for 6 to 8 minutes, stirring occasionally, until browned.
Season with Italian seasoning, smoked paprika, salt, and black pepper.
Split the hoagie rolls and lightly butter the insides.
Toast the rolls under the broiler or in a skillet until lightly golden.
Fill each roll with the kielbasa and pepper mixture.
Top with provolone cheese.
Broil for 2 to 3 minutes until the cheese is melted and bubbly.
Garnish with chopped parsley and serve immediately.