Wash beetroot and cut off leaves. Discard any bruised or yellow leaves and soak remaining leaves in a basin of cold water with spinach.
Steam the 2 varieties of beetroot in 2 separate saucepans until they can be pierced easily with a skewer, then gently rub off skins with your fingers.
Slice beetroot thickly and put in separate bowls. While beetroot is still warm, sprinkle half the walnut oil into each bowl and add a little pepper.
Sauté onion in oil in a small pan for 2 minutes and divide between beetroot.
Shake over red-wine vinegar and taste for salt and sharpness.
Gently dry leaves and arrange on a flat platter.
Peel and slice avocado and arrange among greens.
Combine beetroots gently and quickly and tumble over leaves with all the juices.
This salad looks like a Bonnard painting – all hot pink and sharp green and sunny yellow – and tastes great! Variations are endless: pine nuts, grapefruit, crumbled fetta, potato crisps, to name a few. Proportions are never fixed in a salad like this. It is more important to relax and enjoy its assembly.
