1. Sift together the flours and salt. In a stand mixer, cream the butter until smooth and light. Gradually add the flour mixture and slowly mix until just combined, being careful not to overmix. Add the ¼ cup ice water, combining until the water is absorbed and the dough comes together. Pinch a small bit of dough. If it doesn’t hold together well, mix in another tablespoon of water as needed. Remove the dough from the bowl, knead into a smooth ball, and flatten slightly into a disk. Wrap in plastic wrap, place in the refrigerator, and let rest at least 4 hours or overnight. Let rest 10 minutes at room temperature before proceeding.
2. Preheat the oven to 375° F. Place a paper towel on a cooling rack and arrange the tomato slices on top. Cover with another paper towel. Set aside while the oven preheats, changing paper towels once. In a bowl, toss the zucchini with the salt, pepper, and olive oil.
3. Lay a piece of parchment paper on a work surface and dust lightly with flour. Roll the dough to ¼ inch thickness, about 12 inches in diameter. Transfer the dough on parchment to a baking sheet or pizza pan. Sprinkle ⅓ of the cheese evenly across the crust, leaving about 1½ to 2 inches around the edge. Arrange a layer of tomatoes over the cheese and top with a few pinches of basil. Repeat the tomato layer. Arrange the zucchini slices in an overlapping pattern in a single layer, forming about a 7- or 8-inch circle. Top with the remaining cheese.
4. Fold the outer edges of the dough round over the filling, by about 2 inches all the way around, in an accordion fashion. In a small bowl, whisk together the egg and 1 tablespoon water until frothy. Use a pastry brush to coat the exposed dough with the egg wash.
5. Bake for 20 to 25 minutes, or until nicely browned and the cheese is melted. Remove from the oven and let cool on the baking sheet for about 15 minutes.
Originally published in Organic Gardening magazine, February/March 2014