Preheat oven to 450°F. Line a baking sheet with foil and coat with cooking spray; set aside.
Whisk together buttermilk and egg in a small bowl. Add drained pickles, stirring to coat evenly.
Combine panko, cornmeal, paprika, pepper, and garlic powder in a food processor; cover and process about 20 seconds or until evenly fine. Transfer mixture to a shallow dish.
Working in batches, add a few buttermilk-coated pickles to the panko mixture, stirring with a fork to coat. Shake off excess crumbs. Arrange pickles in a single layer on the prepared baking sheet. Repeat with the remaining pickles. Discard excess buttermilk and panko mixtures.
Lightly coat tops of pickles with cooking spray. Bake 10 minutes. Using a spatula, turn pickles over. Bake 8 to 10 minutes more or until browned and crisp. Serve immediately.