1. Using a mandolin (if possible), slice the zucchini and red onion into thin slices 1/8 inch thick.
Slice into rounds. If you don’t have a slicer, use a sharp knife to slice as thinly as possible.
2. Transfer to a large bowl, sprinkle with salt and mix.
Place a small cast iron pot or dish containing canned goods over the zucchini and onion mixture.
Promotes drainage.
3. After the two hours are up, preheat the oven to 400°F and line a baking sheet (I use a 13″ x 18″ baking sheet) with parchment paper or spray with oil.
4. Transfer the zucchini and onion to a cheesecloth or thin kitchen cloth and pour off as much of the liquid as possible into the bowl with the mixture. Set the zucchini and onion aside. This juice will be used as the liquid base for the scarpaccio.
5. Add the flour, cornmeal, dried rosemary, and nutritional yeast (if using) to the bowl with the zucchini juice. Mix until you get a thick batter similar to pancake batter. To thin, add 1/2 to 3/4 cup water as needed.
6. Add the drained onion and zucchini and gently mix until evenly combined.
7. Pour the batter onto the prepared baking sheet and use a spatula to spread the batter evenly to about 1/2 inch thickness. For a crispier scarpaccio, drizzle the surface with olive oil.
8. Bake for 35-40 minutes until golden and then remove from the oven.
9. Once cooled, remove from baking sheet and cut into 12 squares.
