Measure the following into a medium bowl: 1/4 cup smoked paprika, 2 teaspoons chili powder, 1 tablespoon ground cumin, 1 pinch cayenne pepper, 3 tablespoons packed brown sugar, 2 tablespoons granulated sugar, 1 tablespoon sea salt, and 1 teaspoon ground black pepper.
Use a whisk or spoon to stir the ingredients together until the color and texture are uniform. Press and rub any brown sugar clumps against the side of the bowl with the back of the spoon or a fork to break them up.
Continue mixing for 30–60 seconds, checking for any remaining lumps and ensuring the spices are evenly distributed.
Transfer the rub to an airtight spice jar or tin, wipe the rim clean, and seal tightly.
Store the sealed jar in a cool, dry place away from direct sunlight.