Trim off the stem end of each leek. Cut off enough of the green part to leave a main section of about seven inches. Split the leeks lengthwise in half. Coarsely chop the leeks. There should be about 5 cups loosely packed. Rinse thoroughly in cold water. Drain.
Put the leeks in a saucepan and add enough water to cover. Bring to a boil and simmer, uncovered, about 15 minutes or until tender. Drain thoroughly, reserving 3 tablespoons cooking water.
Put the leeks into a food processor or blender and puree until smooth along with 3 tablespoons cooking water. Scrape the mixture into a saucepan and whisk in 1 tablespoon unsalted butter. Whisk for 2-3 minutes until butter is melted and the puree is creamy.
Flatbread
Preheat oven to 450 degrees F.
Roll out the pizza dough onto a baking sheet coated with cooking spray. Stick the dough all over with a fork to prevent it from puffing up. Drizzle 1 tablespoon olive oil over the dough. Cook dough for 10 minutes.
Remove the baking sheet from the oven and spread the leek puree evenly over the dough. Then, add the mushrooms in an even layer. Drizzle the remaining tablespoon olive oil over the mushrooms; stick the baking sheet bake into the oven and cook for an additional 15 minutes or until the dough is golden brown and the mushrooms are tender.
To finish the flatbread, add the arugula in an even layer over the mushrooms. Garnish with cheese shavings and drizzle with truffle oil. Season with sea salt and black pepper to taste.
Cut into 8 squares and serve hot.
Recipe by Healthy Recipe Ecstasy at https://www.healthyrecipeecstasy.com/leek-and-wild-mushroom-flatbread-with-truffle-oil/