Preheat oven to 350 degrees. Generously butter bottom and sides of 6 (8-ounce) ramekins.

Cut 3 tablespoons of the unsalted butter into small pieces and divide evenly between the prepared ramekins. Sprinkle 2 teaspoons of the brown sugar on top of the butter pieces.

Slice each peach in half and remove the pit. Slice each half into 6 wedges and arrange in a circular pattern on top of the butter and brown sugar. Set aside.

Melt the remaining 2 tablespoons of butter. Set aside to cool a bit.

In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, cinnamon, nutmeg, baking soda and salt.

In a medium mixing bowl, whisk together the buttermilk, vanilla and melted butter. Add to the flour mixture and stir just until combined. Spoon the batter evenly over the peaches. Place ramekins on a large rimmed cookie sheet and bake for around 35 minutes or until the cake is browned on top, firm (but still springy) to the touch and cooked through.

Remove from the oven and cool for around 5 minutes. Run a knife around the edge of one cake. Place a dessert plate on top and invert. Carefully remove the ramekin. Repeat with remaining cakes. Serve immediately, with vanilla ice cream if desired.