Cook spaghetti in salted boiling water until al dente. Reserve some pasta water, then drain.

Season chicken with salt and pepper.

Heat olive oil and butter in a skillet and cook chicken until golden and cooked through. Remove and set aside.

Sauté garlic in the same skillet until fragrant.

Add heavy cream and simmer gently until slightly thickened.

Stir in parmesan until smooth.

Add spaghetti to the sauce, loosening with pasta water if needed.

Return chicken to the pan, toss well, garnish with parsley, and serve.