The blossoms from all species of squash are edible, including summer squash such as zucchini and winter squash such as pumpkin, however some winter squashes have blossoms that tend to be too bitter for eating. The blossoms from each of the different squashes have a slightly different subtle flavor and vary in size. Hubbard, butterball, and pumpkin blossoms are all rather large while zucchini blossoms tend to be smaller. Both the male and female squash blossoms can be eaten. The female flower will often have a tiny edible squash forming behind the blossom, while the male flower is larger and longer. Squash blossoms are especially popular in Italy and Mexico, where they are called "flor de calabaza".
The blossoms are very difficult to find and are available for only a short time during the summer. Try to find organic blossoms to avoid dealing with pesticides. The flowers may be found in the produce section of some well-stocked supermarkets. Your local farmer’s market is also a good bet. If all else fails you can simply grow your own squash and pick the blossoms yourself. However, keep in mind that if you pick the female flowers you will not have mature squash later. Look for blossoms that are brightly colored and tightly closed with no apparent damage. Squash blossoms are extremely perishable and must be used the day they are purchased. The sooner you can prepare them the better, although you can store them in the fridge for several hours if necessary.
The squash blossoms require minimal preparation. Gently peel back a couple of petals and remove the large, stringy sepals and stamens in the center. If the flowers are organic and clean they do not need to be washed. To be sure, look inside the blossom for any dirt or insects. If you see either, gently rinse the blossoms in cold water and let them dry on a towel.
The blossoms can be eaten raw, either alone or as a colorful addition to a salad. They have a mild flavor similar to zucchini. The flowers also can be served with a salad dressing or other sauce. They make an interesting addition to dips, egg dishes like frittatas and omelette, soups, and fried dishes like fritters. They can also be stuffed with a savory filling like cheese, diced vegetables, or rice. The male flowers tend to be larger and therefore are better for stuffing. Add a small dollop of the filling to the inside of the flower and gently twist the ends of the petals to seal the package. The filled blossoms can be sauteed in a pan with a bit of oil or they can be dipped in egg whites followed by seasoned flour or breadcrumbs and deep fried. Yclept also recommends battering and deep-frying the blossoms like tempura.