To make the filling, add the 1/4 cup butter to a 12-inch oven-safe skillet set over medium-low heat.
Brown the butter, stirring often, until it's a rich amber color and smells nutty about 3-4 minutes.
Remove from the heat.
Stir in the peach slices, 1/2 cup brown sugar, bourbon, using, and vanilla.
Bake for 15 minutes.
Reduce the oven to 375 F.
While the peaches are baking, stir the flour, pecans, baking powder, cinnamon, and
Meanwhile, prepare the topping.
In a large bowl, whisk together the flour, ground pecans, baking powder, cinnamon, and remaining 1/2 cup brown sugar.
Stir in the 1/2 cup melted butter and the milk.
Mix until just combined.
Remove the peaches from the oven and dollop batter over the peaches, gently spreading as needed.
Stir the sugar and cinnamon together in a small bowl.
Sprinkle the cinnamon sugar over the batter.
Return the pan to the oven and bake for 20-30 minutes, or until golden on top.
Let cool in pan for 10 minutes.
Notes
Butter: I use salted butter in both the filling and the topping. If using unsalted butter, add a pinch or two of salt to both the filling and the topping.
Peaches: I don't peel the peaches before using. The peaches should be ripe but not over-ripe and smooshy for this recipe.
Bourbon: The bourbon just adds a bit of extra flavor. Feel free to omit it or to use 1/2 teaspoon bourbon flavor instead.
Milk: Any milk from skim milk to whole milk will work in this recipe.