Peel the potatoes and onion and cut into small cubes. Sauté the pieces in a pot with oil and butter.
When the onions are translucent, deglaze with soup or water. Cook until the potatoes are soft.
Continue to puree with a blender or stand mixer, slowly blending in the wild garlic leaves. Do not bring the soup back to a boil along with the wild garlic or it will turn gray.
Season to taste with salt and pepper.
Stir in the whipped cream.