4 tablespoons butter
1 small onion, diced
2 medium baking potato, peeled and diced
2-3 cups chicken or vegetable stock, or hot water
1 1/2 cups milk (low fat is fine)
1/4 cup heavy cream
4 cups chopped mixed greens ( baby spinach, arugula, sorrel, watercress, ramps, or dandelion leaves)
2 Tbs fresh herbs, chopped (flat leafed parsley, rosemary, tarragon leaves)
freshly ground pepper
1. Melt the butter in a heavy bottomed soup pot or large sauce pan over medium heat. When it is melted add the onion and reduce the heat to low. Cover with a lid and cook until the onion is soft, about 5-8 minutes.
2. Add the diced potato, stock (or water), milk and cream to the soup pot. Increase the heat to medium and heat until simmering. Simmer until the potatoes are fully cooked, about 15 minutes more.
3. Add the chopped greens and herbs and simmer uncovered 5 minutes.
4. Puree the soup in a blender or with an immersion blender, until smooth. Season with salt and pepper to taste. Serve hot or cold.