Sweet Potato Soup with prosciutto crisps

Sweet Potato Soup with Prosciutto Crisps

1 1/2 tablespoon unsalted butter
1 large leek (white and light green parts only), thinly sliced, rinsed, and drained
2 small garlic cloves, minced
1 lbs orange sweet potatoes ( about 2 large sweet potatoes; often labeled yams), peeled and cut into 1 inch pieces
about 1 1/2 teaspoons coarse kosher salt
about 1/2 teaspoon freshly ground black pepper
2 ounces thinly sliced prosciutto
1/4 cup heavy cream

Preheat oven to 400 degrees.  Melt butter in a large pot over medium heat.  Add leek and cook, stirring until soft and translucent, about 6 minutes.  Add garlic and cook 2 minutes longer.  Put sweet potatoes in pot; add 3 cups water, 1 1/2 teaspoon salt, and 1/2 teaspoon pepper.  Increase heat to high, bring to a boil, then reduce heat to medium-high and simmer until sweet potatoes are tender, about 10 minutes.  Remove from heat and let cool 10 minutes.  Working in batches, puree soup until smooth.

Prepare the garnish; spread prosciutto slices on a rimmed baking sheet in a single layer.  Bake until crisp, 7 -10 minutes.  Let prosciutto cool completely on baking sheet (about 1 hour), then crumble into tiny pieces and set aside.

Transfer pureed soup to a clean pot set over medium-low heat.  Stir in cream and up to 2 cups water (enough to make soup easy to drink out of cups) Season to taste with salt and pepper.  serve soup hot.