Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned. Drain bacon slices on paper towels and crumble when cool enough to handle.

Bring a large pot of lightly salted water to a boil. Add penne and cook, stirring occasionally, until tender yet firm to the bite. Drain and transfer to a large bowl.

Heat olive oil and butter in a skillet over medium heat until butter is melted and oil is hot. Add onion and cook, stirring often, until tender. Add mushrooms and cook until soft. Add garlic and cook until fragrant. Stir in Italian seasoning, salt, and pepper.

Stir in wine and bring to a boil. Pour in 2 cups chicken stock, add cooked chicken and peas, and bring to a boil.

While the mixture is boiling, mix flour with remaining chicken stock in a jar until well blended. Slowly pour into the boiling mixture, stirring to prevent lumps. Return to a boil and cook until thickened.