Clean and dry the fish. Slice it lengthwise and remove the central bone. Fill the cavity with pesto, close the fish, and tie it with kitchen twine.

Coat the monkfish with flour, dip it in the beaten egg yolk, then roll it in sesame seeds.

Melt the butter in a skillet, then add the monkfish. Cook until the breading is golden brown on all sides. (If serving two, you can cut the fish in half to make it easier to turn in the pan.)

Serve with rice and enjoy.