- 4 lamb kidneys
- 2 tbsp butter
- 1 tbsp olive oil
- 1 large onion, finely chopped
- 2 garlic cloves, minced
- 8 cremini mushrooms, sliced
- 3 tbsp dry vermouth or red wine
- 4 tbsp lamb or beef stock
- 2 tsp Dijon mustard
- Salt and freshly ground black pepper
- Peel away any skin from the kidneys and cut out the core and membranes. Soak in water to cover for 5–10 minutes. Drain and pat dry with paper towels.
- Heat the butter and oil in a frying pan over medium heat. Cook the onion, stirring often, for 2–3 minutes. Increase the heat, add the kidneys and garlic, and cook for 3 minutes, stirring.
- Add the mushrooms, and cook for 2–3 minutes more. Add the vermouth and stock and boil about 1 minute, until slightly reduced.
- Reduce the heat and cover. Cook for 4 minutes, or until the kidneys are tender and cooked through. Stir in the mustard and season with salt and pepper.