Heat the oil in a large lidded pan, stir in the onions and cook for 8 mins until soft. Tip in the mustard seeds and cook for 1 min until toasted. Stir through the curry paste and sizzle for 3 mins.
Mix the beetroot through the spicy onions, then add the chilli, tomatoes and 2 cans of water. Cover and simmer for 30 mins, stirring occasionally, until the beetroot is tender. Remove the lid, turn up the heat and cook until the sauce is thick.
Take off the heat, then stir through the almonds, yogurt and some seasoning. Top with yogurt and serve with basmati rice, if you like.
