Preheat oven to 250 degrees F.
Preferably use a food processor to grate the zucchini and carrot, pushing both through hard and quickly. If a food processor isn’t available, use the large holes of a box grater, pressing firmly so as to get long shreds. Place grated zucchini and carrot in a strainer, over a bowl, add salt, mix together and let sit for about 10 to 20 minutes. Place in a clean towel, wringing to remove as much moisture as possible.
Add to a bowl along with the onions. Add the egg, mix in. Add the flour, cornstarch, and baking soda and beat thoroughly together for a minute or so until the mixture becomes thick like a pancake batter. It should be “gloppy” and thick enough to have to nudge a bit in order to get it to spread. If necessary, add in a little water. Use the batter right away or it can thin out from the moisture of the veggies.
Place oil in pan and heat over medium-high heat. When the oil is hot, working in batches if necessary, use a third of a cup scoop or measure, place dollops of the mixture in the pan and nudge into a circular shape about 3 to 4 inches across. Cook slowly until golden brown, turn and cook the other side. The mixture should be cooked all the way through. If not, lower the heat in the skillet.
To crisp, place on a rack in the warm oven for at least 10 minutes, optional.
Serve immediately, with Asian Dipping Sauce or other sauce of choice, garnished with thinly sliced chives, green onion, or cilantro.
Find it online: https://frugalhausfrau.com/2018/10/12/crispy-zucchini-fritters/