Skin the tomatoes, remove the seeds and cut in brunoise. Cut spring onions also in brunoise. Sweat spring onions in a pan with olive oil, then, add tomatoes. Cook at low heat with the lid on the pan. Later, remove the lid to allow the fluid to evaporate.

Blend basil leaves with oil in a blender until a smooth paste is created. Add to the tomato sauce together with tomato coulis for flavor. Keep warm.