Deep-frying lightly battered vegetables in hot oil creates a pleasantly crispy, golden-brown coating and helps seal in the vegetable juices. Any vegetable large enough to coat in batter is suitable for deep frying. Good candidates include eggplant, onions, peppers, mushrooms, zucchini, cauliflower, carrots, green beans, sweet potatoes or okra. A simple batter consisting of egg and lightly seasoned flour or crumbs won't detract from the natural flavor of the vegetables.
Wash the vegetables, then cut them uniformly. For example, slice zucchini or sweet potatoes into 1/4-inch slices, or cut carrots into 1/8-inch slices. Cut bell peppers into 1/2-inch strips and green beans into 1/2-inch pieces. Fry small vegetables whole, such as mushrooms or okra.
Crack one or two eggs into a small bowl, then beat the eggs lightly with a fork. Place a small amount of flour in a separate bowl, then season the flour with salt and pepper or garlic salt. If you prefer, you can use seasoned breadcrumbs or finely crushed cracker crumbs in place of flour.
Dip the vegetable pieces in the egg, then roll them in the seasoned flour or crumbs. Set the battered vegetables on a baking rack and let them rest at room temperature for about 15 minutes. Drying the vegetables helps the breading stick during the frying process.
Fill a deep fat fryer with oil to a depth of 2 to 3 inches. Oils suitable for deep frying include shortening or canola, peanut, safflower, sunflower or corn oil. Place a food thermometer in the oil, then heat the oil to 375 degrees Fahrenheit.
Place a few vegetables at a time in the basket and lower the basket into the hot oil. Cook the vegetables for about four minutes, or until they turn golden brown. Don't overcrowd the basket because the temperature of the oil may drop, resulting in soggy, undercooked vegetables. Monitor the thermometer and adjust the temperature, if necessary, to maintain a temperature between 375 and 382 F.
Drain the vegetables on a layer of paper towels. Transfer the drained vegetables to a serving plate.