Cut 4 (1/4-inch deep) slices in each bratwurst.

In a saucepan, combine beer, brown sugar, mustard, and black pepper.

Cook over medium heat until the mixture comes to a boil.

Add bratwurst to the boiling mixture.

Reduce heat to low and cook for 5 minutes.

Remove bratwurst from the beer mixture, reserving the mixture.

Place the brats on the grill.

Brush generously with the remaining beer/mustard mixture until browned (about 5-6 minutes).

Mix softened butter with garlic powder and salt.

Spread the garlic butter onto each side of the bun.

Place the buns on the grill and toast until lightly browned.

Place 1 brat onto each bun.

Top with pickle relish, chopped onion, ketchup, and/or mustard.