Preheat the oven to 300℉ (148℃). (Alternatively, use a slow cooker and cover the brisket ¾ of the way with broth or water.)

In a bowl, mix together brown sugar, paprika, salt, black pepper, chili powder, garlic powder, onion powder, and cayenne pepper to make the dry rub.

Pat the beef brisket dry with paper towels. Rub the dry rub all over the brisket, covering all sides. Wrap in foil and place fat side up on a baking sheet. Cook the brisket in the oven for 3 hours (or in the slow cooker for 6–8 hours). Turn off the oven and let the brisket rest for about 30 minutes before slicing.

Remove from oven and rest for 30 minutes before slicing against the grain.

Assemble sandwiches: Place sliced brisket on the bottom half of each bun. Top with barbecue sauce and the top bun.

Make white bean salad: Mix olive oil, lemon juice, cannellini beans, Parmesan, salt, and pepper in a bowl.

Prepare rooibos iced tea: Boil water, remove from heat, and steep tea for 10 minutes. Sweeten with honey or sugar. Cool, then refrigerate. Serve over ice.

Serve: Plate brisket sandwiches with white bean salad, watermelon slices, and rooibos iced tea.