Stuffed squash blossoms require a bit of work, but the "Oohs" and "Aahs" you'll hear when you bring them to the table will make your efforts seem worthwhile.
Chef Matt Millea suggests serving these tasty blossoms on a salad of mixed baby greens dressed with a simple vinaigrette. They're also great as party hors d'oeuvres.
Heat the 1 tablespoon of olive oil in a small skillet over low heat. Add the shallots and garlic, and cook until the moisture has mostly evaporated and the onions have just begun to caramelize. Cool mixture to room temperature.
Place the herbs and goat cheese in the bowl of a mixer and blend at low speed until the herbs are evenly distributed. Add the shallot-garlic mixture and blend again. Taste and adjust seasoning as desired.
Carefully stuff each blossom with some of the herbed cheese. Set aside.
Combine the cornstarch and 1/2 cup of soda water in a small bowl and whisk to blend. Set aside.
Whisk together the flour, baking powder, and cayenne pepper. Add the remaining cup of soda water and stir to blend. Whisk in the cornstarch mixture. Cover the bowl with plastic wrap and set aside for 10 minutes.
Fill a deep frying pan or pot with 2 inches of canola oil and heat to 350 degrees F over medium-high heat.
Dip each blossom into the tempura batter. Transfer gently to the hot oil and cook until golden brown, about 1 minute. Transfer blossoms to paper towels to absorb excess oil. Season with salt and pepper, to taste. Serve hot.