Ingredients
3 tablespoons unsalted butter
1/2 large sweet onion, such as Vidalia, diced medium
2 cloves garlic, thinly sliced
4 cups shelled English peas
Salt and pepper
2 cups buttermilk
6 hard-cooked eggs
2 tablespoons mayonnaise
1 teaspoon Dijon mustard
1 stalk celery, diced small
8 slices white bread
3 cups baby arugula
Preparation
Make the soup: In a medium pot, melt butter over medium-high. Add onion and saute until translucent, 8 minutes. Add garlic and cook until fragrant, 1 minute. Add 1 cup water and simmer until onions are soft, 8 to 10 minutes. Add peas and cook until bright green, 4 minutes; season with salt and pepper. Transfer mixture to a blender and add buttermilk. Blend until smooth, then pour through a fine-mesh sieve into a large bowl, pressing on solids; discard solids. Refrigerate until cold, 1 hour, then season with salt and pepper.
Make the egg salad: Remove yolks from 3 eggs and discard. Coarsely chop eggs and mix with mayonnaise, mustard, and celery; season with salt and pepper. Make sandwiches with bread, egg salad, and arugula. Serve with chilled soup.
