A beautiful alliance for these complimentary tastes and textures !
Finely chop the onion, cut the vitelottes into dices, wash and drain the cress, and prepare the broth.
In a pan, melt the butter and sauté the onion, then add the vitelotte dices, cover with half the broth and cook for 30 minutes.
In another pan, cover the cress with the other half of broth and cook for 20 minutes.
Blend each one and serve immediately.