Heat the oven to 350°F (175°C).

In a large bowl, combine the peach slices with the brown sugar, kosher salt, Meyer lemon juice, vanilla extract, cinnamon, nutmeg, and bourbon if using. Toss well and let the fruit sit at room temperature for 15 to 30 minutes so it releases its juices. For very juicy peaches, use a slotted spoon to lift the fruit out when assembling and simmer the collected juices in a small saucepan for 5 to 10 minutes to make a light syrup for drizzling over the baked cobbler.

Put the granulated sugar in a medium bowl. Add the reserved Meyer lemon zest and rub it into the sugar with your fingertips until the sugar is fragrant and looks like wet sand.

Sift the flour, baking powder, salt, and cinnamon over the lemon sugar and stir until well blended.

Make a well in the center of the dry ingredients. Pour in the buttermilk and vanilla extract, then stir just until the batter comes together; a few lumps are fine. For a quick homemade buttermilk, stir 2 1/2 tablespoons of white vinegar or lemon juice into a 2-cup liquid measuring cup, add milk to the 1 1/2-cup line, and let stand for 7 to 10 minutes.

Add the salted butter to a 12-inch cast iron skillet or a 13 by 9-inch baking dish. Put the pan in the preheated oven until the butter is melted, about 4 to 5 minutes. Remove the pan from the oven.

Pour the batter over the melted butter without stirring, spreading it gently into an even layer. Spoon the peaches and their juices evenly over the batter. Bake for 45 to 50 minutes, until puffed, golden brown, and bubbly around the edges. A half batch will bake a little faster; a deeper 2-quart dish may need extra time.

Set the pan on a wire rack and cool for 15 to 30 minutes before slicing. Serve warm, with vanilla ice cream if desired.