In a medium bowl, add the brown sugar, paprika, onion powder, garlic powder, kosher salt, dry mustard, ground cumin, black pepper, and cayenne pepper. Mix well until combined.
6 tablespoons packed dark brown sugar, 1 1/2 tablespoons smoked paprika, 1 1/2 tablespoons onion powder, 1 1/2 tablespoons garlic powder, 1 1/2 tablespoons kosher salt, 2 teaspoons dry mustard, 2 teaspoons ground cumin, 2 teaspoons freshly ground black pepper, 1/2 teaspoon cayenne pepper