The tangle of zucchini that overflows in Greek summer gardens means that all over the country the number of regional recipes is mind-boggling. Savory pies filled with zucchini are just one category of dishes that call for this summer creeper! There are literally dozens of savory pies filled with zucchini, all slightly varied from place to place and cook to cook. This pie, with Greek yogurt, hails from the north.