Pre heat oven to 180c. Heat 1 tbsp oil and 20g butter in a heavy based flameproof casserole dish over medium high heat. Cook lamb chops, in batches, for 2-3 minutes each side or until browned. Transfer to a plate.

Add remaining oil to pan with onion, celery, carrot and thyme. Cook, stirring for 4-5 minutes or until onion has softened. Add Gravox Traditional Gravy Powder. Cook stirring for 1 minute. Stir in stock and Worcestershire sauce. Return chops to pan. Remove from heat. Arrange potatoes in an overlapping pattern on top. Cover with foil. Bake for 1 hour 30 minutes. Remove from oven. Increase temperature to 220°c. Melt remaining butter, brush potatoes with melted butter. Bake, uncovered for 30 minutes or until potatoes are golden and chops tender.

Serve with steamed green vegetables or salad if desired.