I used a mix of creminis (or baby bellas) and shiitakes, but any mushrooms you love would work in this soup. Examples may include porcinis, chanterelles, chopped portabellas or even button mushrooms although they are a little less flavorful than most other varieties. No matter which mushroom type(s) you chose, just make sure that you slice them approximately the same size for even cooking. Wild mushroom mixes or chef blends work well in this recipe - they add additional flavor and elements of interest.