Fresh mushrooms can be purchased at any grocery store, though I buy a 24 oz container of them at Costco each week for my Garlic Mushrooms (recipe in The Foodie Bar Way) and on my website ( When choosing white button mushrooms, always look for the package with the largest mushrooms, (most health-promoting power). If I am lucky enough to find them at Farmers’ Market (see below), then I certainly pick some up. Keep them cool (right into the fridge, not left on counter), to maximize nutrient content.