Preheat oven to 350 degrees F.
Melt butter in a 10 x 15 inch baking pan. In a shallow dish, combine buttermilk and egg. In another dish combine flour, ground pecans, salt, paprika, pepper, and sesame seeds. Dip chicken in buttermilk then in flour. Place skin side down in melted butter. Turn to coat and leave skin side up. Sprinkle with pecan halves. Bake for 1 hour and 25 minutes. Half way through cooking, toss the grapes onto the baking pan as well.