To make the topping, place the butter in the bowl of an electric mixer fitted with the paddle attachment (you can also use a hand mixer). With the mixer on low speed, add the garlic, shallot, prosciutto, parsley, lemon juice, Pernod, salt, and pepper and mix until combined. With the mixer still on low, add the olive oil slowly as though making mayonnaise, until combined. Fold the panko in with a rubber spatula and set aside.