Step 1

To prepare filling: Place a medium ovenproof skillet in the oven; preheat to 425°F.

Step 2

Combine peaches, 1/4 cup granulated sugar, lemon zest and cornstarch in a large bowl and stir gently. Carefully coat the pan (the handle will be hot) with cooking spray and add the peach mixture. Cover with foil. Bake until the peaches are starting to soften, about 15 minutes.

Step 3

Meanwhile, prepare biscuits: Whisk all-purpose flour, pastry flour, granulated sugar, baking powder, baking soda and salt in a medium bowl. Using your fingertips, rub butter into the dry ingredients until crumbly. Stir in crystallized ginger. Make a well in the center and gradually pour in 6 tablespoons buttermilk, stirring with a fork, until just combined and no streaks of flour remain.

Step 4

Transfer the dough to a lightly floured surface and sprinkle with a little flour. Gently knead the dough 8 times, then pat or roll out to an even 3/4-inch thickness. Using a 2-inch biscuit or cookie cutter, cut the dough into rounds. Reroll the scraps and cut more rounds to make 8 total. Brush the tops with the remaining 2 teaspoons buttermilk and sprinkle with turbinado sugar.

Step 5

Arrange the biscuits over the peaches. Bake, uncovered, until the biscuits are golden brown, about 15 minutes more. Let cool for about 15 minutes before serving.