Pre-heat the olive oil in a large dutch oven over medium-high heat.
Carefully add the sliced sausage to the hot oil in an even layer and let cook, undisturbed, for three minutes.
Stir in the chopped onion, bell pepper, and mushrooms. Cook for ten minutes, until the sausages have browned and the vegetables have softened.
Stir in the garlic and cook until fragrant, an additional minute.
Add in the pasta, fresh basil, diced tomatoes with liquid, chicken stock, and half and half. Season with a pinch of salt and black pepper to taste. Stir together.
Let come to a boil, then reduce the heat to a simmer. Cover and let simmer for 13 minutes.
Remove the lid and stir in half of the shredded cheese and most of the chopped parsley (reserve a tablespoon for garnish). Top with the remaining cheese.
Cover and let cook an additional three minutes.
Remove from heat, garnish with remaining parsley, and serve.