Marinated Goat Cheese and Mushroom Tartines

While shiitake mushrooms and onions are delicious with goat cheese, you can use almost anything in their place in this recipe—try it with any other mushroom, or sautéed radicchio, zucchini, or even apples or peaches. Roasted cherry tomatoes, marinated red bell peppers, or onions caramelized as for French Onion Soup would work well also.