Frozen or tinned spinach is the key to a rich, silky store-cupboard dish that’s best enjoyed with rice or flatbreads

I’ll let you into a secret that every Indian home cook already knows: frozen or tinned spinach makes for the best saag. For a start, there’s not as much water to cook out as there is with fresh spinach, and it breaks down into that gorgeous, oozy-delicious emerald mass more easily than fresh spinach does. Also, there is a general lightening of the human spirit that comes from making something nearly entirely from the freezer or store cupboard (well, it does for me, anyway). That’s the sort of miracle I appreciate at Christmas time.