Clean the spinach, wash it well and cut into large pieces. Peel and finely chop the onion, garlic and ginger. Core the chilli pepper, also cut into small pieces.
Puree everything in a blender or hand blender. If necessary, dilute with a little vegetable stock. Season to taste with salt and pepper. Sprinkle with roasted and roughly chopped cashew nuts before serving.
The sauce goes well with rice and flatbread / naan bread or, not vegan / vegetarian, with fish and chicken breast fillet.