Sweet Pea Soup with Fresh Mint

This recipe is adapted from Sara Foster's book Fresh Every Day. The original recipe call for a fresh mint pesto to be served on top, but I made the soup without the pungent pesto, and just a hint of fresh mint pureed in the soup. Feel free to make the soup with soup with frozen peas if shelling 2 cups of fresh peas is a bit too time consuming.

Serves 6-8

2 tablespoons unsalted butter
2 tablespoons olive oil
1 large yellow onion, chopped
1 1/2 pounds (3-4 medium) Yukon Gold potatoes, peeled and chopped
3 stalks celery, chopped
5 cups chicken or vegetable stock
2 cups fresh or frozen peas
1 head butter lettuce, about 4 cups loosely packed
3 tablespoons chopped fresh mint
salt and pepper to taste

Melt the butter and olive oil in a large saucepan over medium heat. Add the onion and sweat until translucent and soft, about 10 minutes. Add the potatoes and celery and cook for an additional 5 minutes.

Add broth and peas, and bring to a low boil over high heat. Reduce heat and simmer until potatoes are tender, about 15 minutes. Add lettuce and simmer for an additional 2 minutes, or until tender. Stir in the mint, and season with salt and pepper. Remove from heat, and cool slightly. Working in batches, pour the soup into the bowl of a food processor, or a blender, and process until smooth. Pour processed soup back into the pot, check for seasoning, and serve.