Spray a large frying pan with low-calorie spray and place on a medium heat. Add the onion and fry for 10 minutes, stirring occasionally, until softened and golden.
Add the garlic and the lamb steaks. Cook the lamb steaks for 1-2 minutes on each side to seal.
Add the mushrooms, beef stock, red wine stockpot, Worcestershire sauce, tomato puree, mustard, redcurrant jelly, carrots and rosemary and stir.
Simmer for 10-15 minutes until the sauce has reduced slightly, or for a little longer if needed.
Remove the sprigs of rosemary before serving. Taste the gravy and season with salt and pepper, if needed.
Serve with mashed potatoes and vegetables of your choice.