Put a large non-stick frying pan on a medium-high heat and toast the cashew nuts as it heats up, shaking the pan occasionally until lightly golden. Tip the cashews into a pestle and mortar, returning the pan to the heat. Peel and finely slice the onion and place in the hot pan with 1 tablespoon of olive oil and the curry paste. Cook and stir for 8 minutes, then add 1 tablespoon of red wine vinegar. Let the vinegar cook away for 30 seconds, dice and add the paneer, then the spinach. Stir until the spinach wilts and all the liquid evaporates, then taste and season to perfection with sea salt and black pepper. Crush the cashew nuts and sprinkle over the top before serving. Yum.