Steam the pea pods until just tender and pass through a sieve. You can liquidise them, but I found it allowed too much of the fibre into the puree. Reheat the puree gently with the butter and the cream. cut the garlic clove in two and rub over the surface of the meat. Brush the olive oil over the meat and season well with salt and pepper. Grill for a few minutes each side, depending on whether you like your lamb pink, or well done. Roughly chop the basil leaves with a sharp knife and stir into the puree off the heat, season with salt and pepper and serve with the meat.