Place the zucchini and red onion in a bowl, and add the salt. Disperse evenly. Place a weight (like a pot or pan) over top with a can in it to help the zucchini and onion release liquid. Allow to sit for 2 hours.

Preheat the oven to 400F and spray a small baking sheet with oil. I used a 13 x 18.

Two hours later, transfer the zucchini onion mixture to a cheese cloth or thin clean kitchen cloth. Drain as much liquid as possible into a large bowl, and set the zucchini and onion aside.

Add the flour, nutritional yeast, dried rosemary and cornmeal to the bowl with the reserved liquid. Gently mix until a batter is formed, adding ½ cup to ¾ cup of additional water as needed to thin. The mixture should be like pancake batter.

Add the vegetables into the batter and mix until evenly dispersed. Transfer the batter to the oiled baking dish and spread so it is in an even layer. Spray the top with more oil, then place in the oven for 35 minutes, until lightly crisped. Store in a sealed container in the fridge for up to 4 days.