If sausage has casing around it, remove from sausage and crumble meat in a bowl. Set aside. Sauté leeks and garlic in 2 tablespoons butter for 30 seconds. Add crumbled sausage and mushrooms. Cook stirring occasionally, until browned. In a large bowl, tear bread into small pieces and add milk and 1/4 cup melted butter. Soak bread in mixture for five to 10 minutes.

Once sausage mixture is cooked, add to the bread/milk bowl and mix well with your hands. Stuff turkey with mixture. Alternately, spread evenly about 1-inch thick in an 8x8-inch baking dish. and pop in the oven alongside the turkey. Bake until golden on top.

*For a vegetarian version, replace sausage with 1 medium fennel bulb, chopped.