Ethiopian-spiced lamb

Method

1. Begin the day before serving. Mix together the spice rub ingredients in a small bowl. Put the lamb in a dish and score the fat in a shallow criss-cross pattern. Generously dust the lamb with the spice rub, pressing it into the slashes. Cover with cling film and chill for 12-24 hours. Take the lamb out of the fridge at least an hour before you want to cook it, to let it come to room temperature.
2. For the onions, melt the butter in a small saucepan and add the ginger and spices. Simmer very gently for 30 minutes, skimming away any foam that rises to the surface. When the milk solids have browned and sunk to the bottom, strain the butter using a piece of muslin or a clean J-Cloth (discard what’s left in the cloth).
3. Gently fry the onions and garlic over a medium heat in half the spiced butter until starting to brown, then remove from the heat. 
4. In a frying pan over a medium-high heat, brown the lamb, fat-side down, until the fat starts to melt, then turn over, turn down the heat slightly and fry for another 5 minutes or so until medium-rare. Leave to rest while you reheat the onions, then pile them into bowls. Slice the lamb thickly across the grain, divide among plates, then spoon on a little spiced butter. Sprinkle with parsley and serve with lemon wedges.