Prepare a bed of very hot coals. Heat a very large, heavy skillet over hot coals or high heat of range until at smoking point.
Meanwhile, combine onion powder, pequin or cayenne, garlic juice or powder, thyme, mustard and several grinds of black pepper. Set lamb chops on large baking sheet; trim off excess fat or membrane.
Melt butter in small saucepan. Brush 1 side of each chop; evenly divide 1/2 spice mixture among chops, gently rubbing mixture in. Turn chops, brush with butter and rub in remaining spices. Add remaining butter to skillet.
Immediately add chops, making certain skillet stays very hot. Grill quickly, only 1-2 minutes per side, turn chops only once. Add more butter as needed.
Chops should be charred on outside and rare on inside. Serve hot on warmed plates.
Servings: 4