Make the Peach Cobbler Filling
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, vanilla extract, and cornstarch. Let sit for 5 minutes to macerate as you make the topping.
Make the Cobbler Biscuit Topping
In a large mixing bowl, whisk together the all-purpose flour, brown sugar, baking powder, and kosher salt. Use a pastry cutter to cut the butter into the dry ingredients, until the butter is cut into pea-sized pieces and the mixture looks like coarse meal.
Mix in boiling hot water until all ingredients are just combined with a baking spatula.
Add the macerated peaches and their juices into a 9 or 10 inch cast iron skillet. Drop spoonfuls of the topping over the peaches using a cookie scoop or two spoons.
Bake
Mix together the cinnamon and sugar in a small bowl and generously sprinkle the cinnamon sugar mixture over the peach cobbler topping.
Bake in the preheated oven for 30-35 minutes, or until the peach cobbler is browned and bubbly.
Remove the peach cobbler from the oven and let cool for 15 minutes before serving. Serve warm, topped with vanilla ice cream.