Cooking Tips: After opening store any unused mushrooms in the box they came in or a brown paper bag. Keeping the mushrooms in clusters will keep them fresher longer. Washing our cultivated mushrooms is not necessary and will change the texture. Simply trim the bottoms and they are ready for use in your favorite recipes. White beech mushrooms can be used in place of button mushrooms and make an elegant addition to roast meats, poultry, and seafood dishes, bisques, sauces, and stir-fries.