Vegetable Tempura Fries that's just as crispy and light as you get it from (a good) restaurants. I actually think it's better than most restaurants. Use the same batter recipe to make shrimp and other tempuras.
Peel sweet potatoes and carrots. Cut them into thin french-fry sized match sticks. The potato and carrot sticks should be cut roughly the same thickness because you want them to both cook evenly.
Clean and cut both green onions and onions so that they are roughly similar in length to potato and carrots. Onions cook quicker so they can be a little thicker.
Add all the vegetables into a large bowl and toss with hand.
Heat oil: Heat about 6 cups of vegetable or canola oil for deep frying on medium high heat until it reaches roughly 335 - 350 F. See my tips above on measuring temp of oil without a thermometer.
Make batter - add all batter ingredients and mix until they are no big lumps. Do NOT overmix. If adding ice cubes, DO NOT add them until you are all ready to start frying. You want to keep this batter cold so do not wait too long before using it.
Add vegetables to batter and mix to coat evenly. I use long chopsticks or hands - this works best.
Fry them! By now, your oil should be hot enough. The oil temperature should be around 340 -355 ℉ (170-180 ℃). Best to start at 355 because it will cool down once you add your vegetables. Keep the heat between med-high and medium and it should work.