Heat 1 tbsp of the oil in a deep frying pan over a medium-high heat. Add the paneer cubes and fry for 5 mins, turning regularly, so each side is golden brown. Remove with tongs and put on a plate lined with kitchen paper.
Put the onion, ginger and garlic in a food processor with a splash of water and blitz until completely smooth. Heat the remaining oil in the frying pan over a medium-low heat. Add the onion mixture and a pinch of salt, and fry for 10 mins or until lightly golden. Add the korma paste and cardamom, and fry for 1 min. Stir in the ground almonds and fry for 1 min to make a thick paste.
Add the stock, bring to a simmer and cook for 5-10 mins, uncovered, or until reduced a little. Add the spinach to the sauce and cook for 5 mins. Stir through the yogurt and paneer, and season generously. Serve with rice or warm naan breads.