Stir-fry recipes are true weeknight heroes since they come together quickly and are packed with flavour. Plus, by pairing an iron-rich animal-protein, like beef liver, with a plant-based source of iron, like fresh spinach, this recipe has an impressive iron punch. Finish the dish with lemon juice to boost iron absorption and perk flavours. Liver is the most delicious when it is still a bit pink inside and is slightly springy to the touch.