Preparation Preheat oven to 325°F. Place bread on baking sheet. Bake until beginning to dry, about 12 minutes. Cool completely. (Can be prepared 1 day ahead. Cover bread and store at room temperature.) Butter 11x7x2-inch baking dish. Melt 4 tablespoons butter in large pot over medium-high heat. Add mushrooms and sauté until mushroom liquid evaporates and mushrooms are beginning to brown, about 8 minutes. Transfer to large bowl. In same pot, melt 4 tablespoons butter over medium-high heat. Add celery and cook until softened, about 4 minutes. Add leeks; cook until vegetables are tender, about 4 minutes longer. Add sautéed vegetables, parsley and dried herbs to mushrooms; toss. Season with salt and pepper. Add bread cubes and oysters to vegetables in bowl; stir to combine. Mix in reserved 1/2 cup oyster juices and Turkey Stock. Season with salt and pepper. Use 9 cups stuffing for turkey. Transfer remaining stuffing to prepared baking dish; cover with foil and chill until ready to bake. Bake stuffing, covered, at 325°F, until heated through, about 45 minutes.
Preparation Preheat oven to 325°F. Place bread on baking sheet. Bake until beginning to dry, about 12 minutes. Cool completely. (Can be prepared 1 day ahead. Cover bread and store at room temperature.) Butter 11x7x2-inch baking dish. Melt 4 tablespoons butter in large pot over medium-high heat. Add mushrooms and sauté until mushroom liquid evaporates and mushrooms are beginning to brown, about 8 minutes. Transfer to large bowl. In same pot, melt 4 tablespoons butter over medium-high heat. Add celery and cook until softened, about 4 minutes. Add leeks; cook until vegetables are tender, about 4 minutes longer. Add sautéed vegetables, parsley and dried herbs to mushrooms; toss. Season with salt and pepper. Add bread cubes and oysters to vegetables in bowl; stir to combine. Mix in reserved 1/2 cup oyster juices and Turkey Stock. Season with salt and pepper. Use 9 cups stuffing for turkey. Transfer remaining stuffing to prepared baking dish; cover with foil and chill until ready to bake. Bake stuffing, covered, at 325°F, until heated through, about 45 minutes.