M&S Rosa Verde Salad Washed and ready to eat rosa verde salad, with a mild and sweet flavour. Our rosa verde mix contains beautifully smooth and buttery red and green butterhead lettuce with delicate lambs lettuce for a distinctive flavour. It’s the perfect pairing in a Tuna Niçoise salad with black olives, red onions, boiled eggs and a glug of French vinaigrette.