1.Preheat An Outdoor Grill For High Heat And Lightly Oil Grate. 2.In A Large Bowl, Combine The Ground Beef With The Garlic Powder, Ground Black Pepper And Celery Seed To Taste. Mix Well And Form Into 8 Flat Patties. 3.Spread 4 Of The Patties With Your Favorite Condiments, Then Place The 4 Remaining Patties Over These And Seal The Edges. 4.Grill Over High Heat For 5 Minutes Per Side, Or To Desired Doneness. Use Either Two Spatulas To Turn, Or You Could Use A Fish Basket.