Zucchini and squash blossoms are (I think) one of the most delightful summer vegetables. They should look firm and fresh, and ideally should be just slightly open.
They're quite perishable, and should be used the day they're bought, or at the most the day after. If your local supermarket doesn't carry zucchini blossoms, you may be able to get them from a farmers' market, or from a farm produce stand. As a last resort, if you have a vegetable patch, you can plant some zucchini. It's worth the effort.
When you get them home put them in the crisper section of the refrigerator until it comes time to cook them. Then wash them gently, pat them dry, and remove the pistils. You're now ready to proceed.
My favorite way of enjoying zucchini blossoms is dipped in batter and fried, because the crunchy saltiness of the crisp golden batter beautifully complements the sweetness of the flower itself, without overshadowing the flower's delicate flavor. Here's a simple recipe that supposedly will serve about 6, though in my experience it's being optimistic:


