Last night made something similar, except I used 2 sticks of celery, 8 large mushrooms, 4 asparagus spears, and 2 heaped tablespoons of cauli rice. Simmered in homemade chicken stock, then blitzed with a blender, returned to the pan and heated with 2 heaped tablespoons of thick double cream to thicken.... lovely! Much more appetising than lettuce IMO and hardly much more carbs.