How to Make It
In a medium saucepan, cook the blackberries with the sugar over moderately high heat until they are softened but still hold their shape, about 5 minutes. Transfer to a bowl and stir in the mint, horseradish, lime juice and the 1 tablespoon of olive oil. Season with salt and pepper and let cool.
Light a grill or preheat a grill pan. Brush the lamb chops with olive oil and season with salt and pepper. Grill over a medium-hot fire until medium rare, about 2 minutes per side. Serve with the blackberry relish.