1. Preheat your oven to 350°F (175°C). Add the unsalted butter to a 9×9-inch baking dish and place it in the warming oven just until the butter is fully melted, then remove the dish and set it aside.

2. Peel the peaches if desired, then slice them into even wedges. Add the sliced peaches to a mixing bowl along with the sugar for peaches, lemon juice, vanilla for peaches, cinnamon, and nutmeg. Toss gently to coat and let the mixture sit for about 10 minutes so the peaches release their juices.

3. In a separate bowl, whisk together the flour, sugar for crust, baking powder, and salt until well combined. Pour in the milk and vanilla for crust and whisk just until a smooth batter forms with no dry pockets remaining.

4. Carefully tilt the baking dish so the melted butter coats the bottom evenly. Pour the batter over the melted butter in the dish, making sure it covers the bottom in an even layer. Do not stir the butter and batter together.

5. Spoon the peaches and all of their juices evenly over the batter in the baking dish. Spread them out so there is fruit in every bite, but avoid stirring them into the batter.

6. If using, sprinkle the turbinado sugar evenly over the top of the peaches and batter to create a crunchy, sweet crust as the cobbler bakes.

7. Transfer the baking dish to the oven and bake for 38–45 minutes, or until the cobbler is puffed, the top is golden brown, and the peach juices are bubbling thickly around the edges. A toothpick inserted into the crust should come out mostly clean.

8. Remove the cobbler from the oven and let it cool for 10–15 minutes so the juices thicken slightly and the topping sets.

9. Serve warm, spooning the peaches and sweet crust into bowls. Top with vanilla ice cream, whipped cream, or a dollop of Greek yogurt, if desired.