Zucchini and cauliflower are a great combo in making vegetable-crusted pies. While the zucchini is moist, the cauliflower is less so and when combined, the level of moisture that cooks out of the pie while it's in the oven seems to work quite well. Not cooking the cauliflower before it's baked also seems to work well; the combination of the zucchini and the cauliflower when cooked provides the right amount of toothy-ness.
To prep the zucchini, I use my handy little Japanese mandoline to cut the zucchini into batons.
That little tool is a major lifesaver; it makes short work of slicing anything you like to whatever thickness you need. If you don't already have one, I strongly recommend getting one. They are very inexpensive and are typically available at Japanese hardware and department stores (if you're local, go to Soko Hardware in Japantown) or on Amazon.
BE AWARE, however, the Japanese mandoline is VERY sharp, and I strongly recommend that you DO NOT IGNORE the label that says, "WATCH YOUR FINGERS!" If you slip, you will end up in the ER getting at least a stitch or two. Or maybe more. I have learned this lesson very well.
I salted the zucchini and let it sit for ~15 minutes to exude moisture then rinsed it and squeezed the daylights of it in a length of cheesecloth.
In the meantime, I prepped the cauliflower, I trimmed the head and then pulsed half of it in the food processor until super fine, slightly larger than grains of sand.
I noticed there was a head of broccoli the fridge so I cut that up, and cut up the other half of the cauliflower, tossed both of them in lots of olive oil, and stuck them into a preheated oven at ~450 degrees. I let them cook for ~15 minutes, until their edges started to blacken.
Going back to the zucchini, to combine both the zucchini and the uncooked cauliflower (in the work bowl of the food processor), I used my hand to incorporate the ingredients using almond and oat flour, one and a half egg, a half cup of cheddar cheese, some fresh herbs, and a little salt and pepper. I patted the dough with my hand onto a piece of parchment paper to a thickness ~1/4" and formed a lip around the edge to make a crust.
I put the pie into the oven, preheated to ~400 degrees, on a rack (rather than a stone, on the oven floor) and let it cook for ~12 minutes, until the edges started to brown.
I took the par-baked pie out of the oven, cranked the oven back up to 500, added tomato sauce and the roasted vegetables, and put it back into the oven to cook for about ~10 minutes.
The pie came out great -- the lack of cheese on top of the pie made no difference; the flavor of the roasted vegetables and the vegetables in the crust was enough.
Oh, and I spied a few strawberries lying around, and with left-over pie makings, I took a risk and made another pie using the most tiny pieces of roasted broccoli and cauliflower -- those super delicious crispy bits, like what you get at the end of a basket of french fries, you know what I mean? -- and sliced strawberries on top. Quite honestly, it tasted amazing.