A light summer zucchini pie that's golden and puffy, layered with tender thin-sliced zucchini and plenty of cheese. Easy to prepare and delicious served warm or at room temperature.
Position a rack in the oven center and preheat to 350°F. Grease a 9-inch deep pie dish with nonstick spray and set aside.
Mix:
In a large bowl, combine both flours, baking powder, thyme, black pepper, and salt. Whisk the eggs into the dry mix until a very thick batter forms.
Saute:
Melt the butter in a medium skillet over medium heat, add the sliced onion, and cook until softened and browned in spots, about 10 minutes. Let the onion cool briefly, then fold it into the batter.
Fold:
Gently fold the thinly sliced zucchini, grated cheddar, and 1/4 cup of the Parmesan into the egg-flour mixture until the ingredients are evenly distributed.
Spoon the mixture into the prepared pie dish, smoothing the zucchini slices into an even layer. Sprinkle the remaining 2 tablespoons of Parmesan evenly over the top.
Bake until the pie is puffed, golden on top, and set in the center—about 30 to 40 minutes. A butter knife inserted into the middle should come out clean when done.
Remove from the oven and garnish with chopped fresh basil if using. Let the pie rest for 10 minutes before slicing. Serve warm or at room temperature.