Spicy Italian Sausage & Pepper Pasta

Ingredients

• 1/2 pound pasta of your choice
• 1 pound Italian sausage (I used spicy)
• 1 tablespoon olive oil
• 4 tablespoons butter, divided
• 1 small package frozen onions and colored bell peppers
• 3 cloves garlic, minced
• 1 teaspoon flour
• 1 cup heavy whipping cream
• 1 teaspoon Dijon mustard
• Freshly grated Parmesan for serving (I forgot this and it was still so good!)