Experiment with a variety of vegetables when making these snacks: Turnips, sliced paper thin and lightly fried in garlic flavored oil, have a wonderful texture.
Place 3/4 cup plus 2 teaspoons cold water in a small bowl. Add the egg, flour, baking soda, and salt to the water. Whisk together ingredients. Place the batter in the refrigerator, and chill 30 minutes.
Wash and trim all the vegetables. Cut the vegetables into small pieces, no more than 4 inches in length and width and no more than 1/2 inch thick. Cover the cut vegetables with a damp paper towel, and place in the refrigerator to chill, about 15 minutes.
In a medium saucepan over medium-high heat, heat both vegetable oil and sesame oil until a deep-frying thermometer registers 375 degrees. Set the bowl of chilled batter over a large bowl filled with ice water. Working in batches, dip vegetables in batter, then fry until golden, crisp, and cooked through, 2 1/2 to 3 1/2 minutes. Blot cooked vegetables on paper towels, and sprinkle with salt. Repeat with the remaining vegetables. Serve with Dipping Sauce for Tempura Vegetables.
You can use any type of vegetable in this recipe. If you choose root vegetables, cut them a little thinner since they take longer to cook than other vegetables.