Grate the potatoes and onions using the grating disk of the food processor. Do not process with the standard blade or in a blender. Place a colander large enough to hold the grated potato-onion mixture over a pot or bowl. Remove the grated potato-onion mixture from the food processor bowl and put in the colander. Let stand for five minutes.

Press down on the mixture to quicken the draining process. Repeat this two or three more times at five minute intervals. The ingredients will be ready when the mixture no longer squishes when pressed (approximately 15 minutes).

Repeat the grating procedure with the zucchini. Place zucchini shreds in their own colander over a bowl to catch the liquid. Let stand five minutes. Sprinkle liberally with salt and toss well. After five minutes, press down on the mixture to hasten the draining process. Repeat this pressing step until the mixture no longer squishes. For added insurance, place the zucchini shreds on a stack of paper towels and blot up any residual moisture.

Grate the carrots. Combine the shredded and drained potatoes, onion, zucchini with the grated carrots. Add the egg and mix well. Add the matzah meal a little bit at a time until the mixture just starts to dry out.

Carefully, pour the liquid out of the bowl/pot which was placed under the colander for the potatoes and onions. At the bottom of the bowl, you will find a thick, starchy paste (potato starch). Scrape this paste out of the bowl and add to the potato-carrot-onion-egg mixture, blending well. Drop by the spoonful into hot oil and fry until golden and crisp on both sides. Drain on paper towels.