Combine the All-Purpose Flour (3 cup), Garlic Powder (1/4 teaspoon), Salt (1 teaspoon), Ground Black Pepper (1/4 teaspoon) and Granulated Sugar (1 tablespoon) in the bowl of a standing mixer and mix with a fork.
In a separate bowl, whisk together the Instant Dry Yeast (2 1/4 teaspoon) and Milk (1 cup) until yeast is dissolved. Add the yeast mixture and Butter (1/4 cup) to the mixer bowl and mix with a wooden spoon until loosely combined.
Place the dough hook on the mixer and knead on low speed for 6-8 minutes until a smooth ball of dough is formed. You can also knead by hand on a floured surface for 8-10 minutes.
Place dough in a lightly greased bowl and cover with plastic wrap. Let dough rest until it doubles, about 2 hours.
Grate the Onion (3/4 cup).
Grate the Sharp Cheddar Cheese (3/4 cup) and Asiago Cheese (3/4 cup).
When the dough has about 15 minutes left to raise, combine grated onion and cheeses, Dried Dill Weed (1 teaspoon), Sea Salt (1/2 teaspoon), and Ground Black Pepper (1/2 teaspoon) and mix well.
Remove dough from bowl and roll out on a floured surface into a long, narrow rectangle about 8-by-24-inches in size.
Spread filling evenly across the dough, leaving a half-inch border on all sides.
Carefully roll up the dough along one of the long sides to form a long, narrow log. Cut the log into 3/4″ segments using a sharp serrated knife, which should yield 32-36 pieces.
Spray a 9-by-13-inch pan and an additional 8-by-8-inch pan with cooking spray. Place the pieces into the pans leaving about 1/2″ of space between them.
Melt Butter (1 tablespoon) and brush the tops of the buns. Cover the pans with plastic wrap and allow to rise for about an hour in a warm place.
Preheat oven to 350 degrees F (180 degrees C) before the hour is up, so it's ready to go.
Remove plastic wrap from pans and bake for about 25 minutes until tops are golden and the cheese is slightly bubbly.
Best served immediately, but they also reheat nicely for several days after baking.