Using your hands combine the minced beef in a bowl with the onion, garlic and egg and generously season with salt and black pepper.
Divide the mince into 4 parts and roll each piece into a ball, then form into flat patties roughly 10cm wide and about 2cm thick.
In a small bowl, combine all the coffee rub spices together.
Lightly coat the burger patties in olive oil and generously apply the coffee rub.
In the meantime, combine all the BBQ sauce ingredients in a medium size bowl and season well with salt and freshly ground black pepper. Set aside.
Heat a griddle pan on a medium-high heat, brush with a splash of oil and cook patties for 3 or 4 minutes on each side or to your liking. Use a spatula to lightly press down on them, making sure each burger is in full contact with the pan.
Build your burgers by topping the rolls with smoky BBQ sauce, coffee coated patties, cheddar cheese, red onion and fresh, peppery rocket leaves.