Boil the sprouts in a large pan of salted water for 4 minutes. Drain and tip into a bowl of iced water. When you are ready to use them, drain the Brussel sprouts again and set aside.
Heat the butter in a large frying pan over a medium heat. Add the almonds, cranberries, garlic and sage. When the almonds just begin to turn brown add the Brussel sprouts and stir until the Brussel sprouts are coated in the nut mixture and just start browning.
Squeeze over the lemon juice, season with salt and black pepper and serve immediately.
