Spiced Peach Mixture
Preheat your oven to 425 degrees F (220 degrees C/200 degrees C in a fan-forced oven).
In a large mixing bowl, stir together sliced peaches, brown sugar, cinnamon, ginger, nutmeg, lemon zest, lemon juice, bourbon, vanilla extract, and cornstarch. Let sit for 5 minutes to macerate as you make the topping.
To make the dumplings
In another large mixing bowl, whisk together the all-purpose flour, granulated and light brown sugars, baking powder, and kosher salt. Use a pastry cutter or food processor to blend the butter into the dry ingredients, cutting the butter up into pea-sized pieces and the mixture looks like coarse meal. Mix in boiling hot water (in a bowl if using the food processor) until just combined with a baking spatula.
Add the macerated peaches and their juices into an 8x11 or 9x9 baking dish. Drop spoonfuls of the topping over the peaches using an ice cream scoop or cookie scoop.
Bake
Mix together the cinnamon and sugar in a small bowl and generously sprinkle the cinnamon sugar over the entire peach cobbler.
Bake in the preheated oven for 30 minutes, or until the peach cobbler is browned and bubbly.
Remove the peach cobbler from the oven and let cool on a wire rack for 10-15 minutes before serving. Serve warm, topped with vanilla ice cream.