Rinse and pat dry the drumsticks. Mix the mustard and the mayonnaise together in one bowl. In a separate bowl, mix the bread crumbs, Parmesan, Italian seasoning, garlic powder, and black pepper.
Using a pastry brush, coat a drumstick liberally with the mayonnaise/mustard mixture, then roll the drumstick to coat in the breadcrumbs. Lay the coated drumstick on a baking sheet. Repeat for all drumsticks. Bake drumsticks at 350F for 45 minutes or until done through and juices run clear.