Peel and finely chop the shallots. Mix it with mustard and vinegar, then add the olive oil. Salt and pepper. Wash and thoroughly dry the lettuce. Fill them for 5 minutes before serving. Remove the bones from the fish, then divide each piece of fillet into two parts, making diagonal cuts, roll them in the sesame seeds, then fry in butter on each side until golden brown over high heat for 2 minutes, salt and pepper. Arrange salad on plates, put the pieces of golden fillet with crispy crust.