6 tablespoons dark brown sugar, packed 1 tablespoon smoked paprika 1 tablespoon chili powder 1 tablespoon red pepper flakes 2 teaspoons garlic powder 1 teaspoon fennel, ground and toasted 2 tablespoons kosher salt 1 tablespoon coarse black pepper 1/2 tablespoon mustard powder 2 tablespoons softened, unsalted butter or olive oil One 4-pound chicken, giblets removed 4 cloves garlic, peeled and smashed One 12-ounce can of beer -- drink or pour out half (lager or ales work nicely, but feel free to experiment with other beers you like)