1. Heat the olive oil and butter in a large pot over medium-high heat. Add the shallot and garlic and cook until softened, about 5 minutes.
2. Add the wine, cream, and parsley and season well with salt, then add mussels. Give it a good stir, cover the pot, and cook until heated through, about 5 to 6 minutes (for fresh mussels, cook until they open and are cooked through, about 10 to 15 minutes).
3. Divide the mussels and sauce between 2 bowls and serve with the crusty bread.