Preheat Oven: Preheat oven to 350 degrees F.
Create Topping: Add brown sugar, cinnamon, ginger, and flour to a large bowl, add cold cubed butter and use a pastry cutter to cut in butter until a crumbly topping is formed. Fold in oats.
Prep Peaches: Pit and slice peaches - peeled or unpeeled. Add lemon juice, maple syrup, almond extract, cinnamon, ginger, nutmeg, and gently mix.
Create Filling: Add 2 tablespoons of butter to the cast iron skillet and heat over medium to melt butter. Turn off the heat, add the peaches. Do not mix, let the butter coat the bottom of the pan.
Add Topping: Sprinkle the crumble topping over the peaches in an even layer covering all of the peaches.
Bake: Add cast iron to the middle rack of the oven and bake for 45 minutes until the topping is golden.
Serve and Enjoy with your favorite vanilla ice cream!