For the mousse, slowly poach the spring onion and leek for 20 minutes, then add the peeled and deseeded tomatoes and poach for a further 10 minutes, at which point add the liver cut into small pieces and cook over a very low heat for a further 15 minutes, season with salt and pepper and blend to obtain as fine a paste as possible. Set aside in a bowl, when cold. Carefully mix with the egg whites until stiff, obtaining a very fluffy mousse. For the ratatouille cream, poach all the ingredients very finely chopped, except the tomatoes, over a very low heat for 20 minutes, at which point add the chopped tomatoes and the spices, oregano, thyme, fresh basil, ground cumin, salt and pepper, and pass through the blender.
Place and set aside cold. Assemble in a cocktail glass, placing the ratatouille cream at the base, followed by the liver mousse and, finally, the sautéed garlic that we have julienned and then fried in olive oil.