1. Start with the pastry (at least an hour ahead). Put both flours in a food processor, or, if making this by hand, a large bowl. Add the butter and pulse in the food processor, or rub in by hand, until it resembles fine bread crumbs. Add enough ice water to bring the mixture together in a ball, starting with 1. tablespoons and working up to no more than 3 tablespoons, as needed. Again, either use a food processor here, being careful not to overwork the dough, or cut the water in with a table knife. Form the pastry into a flattened disc and roll out between sheets of parchment or wax paper until it is about ¹∕8 inch (3 mm) thick. Unpeel the top sheet of paper and flip the pastry on to a 2-inch (5 to 6 cm) deep, 9-inch (23 cm) pie dish or tart pan. Unpeel the second sheet of paper (now on top) and press the pastry into the pan, trimming the edges flush with the dish. Keep the paper. Cover with plastic wrap and chill for 30 minutes, or up to 48 hours.
2. Preheat the oven to 400F (200C). Line the pastry with a saved paper sheet and fill with baking beans or raw rice. Bake for 15 minutes until the pastry is set and no longer looks wet. Remove the paper and beans and return to the oven for 5 to 6 minutes, until lightly colored.
3. Reduce the oven temperature to 350F (180C). Put the zucchini in a sieve and sprinkle with a generous pinch of salt, tossing to distribute evenly. Set aside for 10 minutes, then press down on them to drain. Put into a clean kitchen towel and wring out any remaining liquid very forcefully.
4. Combine the zucchini, peas, dill, capers and lemon zest in a bowl. In a separate bowl, whisk the buttermilk, half the ricotta and the eggs with a little salt and a lot of pepper. Fold the 2 mixtures together. Pour into the crust and dot with the remaining ricotta. Bake for 25 to 30 minutes, until just set. Set aside for 15 minutes so the filling can settle.
5. Toss the tomatoes with the oregano, lemon juice and extra virgin olive oil to taste. Season and serve the salad with slices of the warm or cold tart.
Recipe from Good Veg: Ebullient Vegetables, Global Flavors–A Modern Vegetarian Cookbook © Alice Hart, 2016. Photographs © Emma Lee, 2016, 2017. Reprinted by permission of the publisher, The Experiment. Available wherever books are sold. theexperimentpublishing.com