Sous Vide Sweet Potato Bisque

Ingredients

• 2 medium sweet potatoes, peeled and cut into ¼-inch-thick slices
• 1 cup diced leeks, white part only
• 1 cup vegetable stock
• 3 tablespoons unsalted butter
• 1 tablespoon freshly grated ginger
• 1 clove garlic, minced
• 1 bay leaf
• Kosher salt and freshly ground black pepper
• 1 cup heavy cream