This open-face sandwich (the French call it a tartine) is wonderfully flavorful. It’s lovely for a brunch and completely perfect as an appetizer or on a buffet table. It’s easy to make the pea purée up to a day before and simply put it together before serving; then collect the oohs and aaahs.
chopped shallot (about 1 large shallot)
Heat the olive oil in a small frying pan set over medium-high heat until it ripples. Add the shallot and cook, stirring and shaking the pan, for 2 minutes, or until translucent. Set aside.
Preheat the oven to 350ºF. Prepare a rimmed baking sheet with a misting of nonstick vegetable oil spray. Set aside. Prepare a bowl of cold water and set aside, fairly close to the stovetop.
Rinse the peas in fine-mesh strainer under cold running water and swish with your fingers to remove any dirt. Remove and discard any peas that have sprouted. Set aside. Bring a large pot of salted water to a boil, add the peas and blanch for 2 to 3 minutes and then transfer them to the cold water in a fine-mesh strainer to shock them and stop the cooking. They should not be cooked through, and the green should be vibrant. When cooled, drain and reserve ¼ cup of the peas.
In the bowl of a food processor, add the remaining peas, the salt, sugar, and lemon juice, and purée until the mixture is chunky and the peas are well broken up. This is a rustic pea purée, not a pea soup. You could actually chop this on a chopping board if you don’t mind the time or mess.
Transfer the pea purée to a medium-sized mixing bowl and stir in ½ teaspoon tarragon and the parsley.
Gently fold the egg whites into the pea purée, and then set aside while you prepare the open-faced sandwich.
Slice the top section off the loaf of bread and reserve for bread crumbs or another use. Cut the remainder into 4 sections between 5 and 7 inches long.
Place the bread on the prepared baking sheet and bake for 3 to 4 minutes, just to warm and toast it slightly. Turn the bread over and toast for another 2 minutes. The edges brown lightly.
Place one-fourth of the pea mixture on each piece of bread, then top each with one-fourth of the aioli, followed by one-fourth of the crumbled cheese and the pea shoots. Garnish with the remaining ¼ cup peas and the minced tarragon. Serve immediately.