In a large bowl, add flour, granulated and brown sugar, cinnamon, and nutmeg. Whisk together until incorporated and there are no lumps.
Add in the butter and vanilla. Using a fork, cut in the butter until the butter is the shape of small pebbles.
Place in a freezer bag and freeze for at least 1 hour. I froze mine over night.
Filling
Preheat oven to 350 degrees.
Either blanch or peel the peaches. I blanched mine by placing them in boiling water for about 1 minutes and then immediately placing them in ice water to cool down.
In a large bowl, add in the granulated and brown sugar, cornstarch, and cinnamon. Whisk until everything is incorporated and there are no lumps.
Add in the diced peaches and coat them with the sugar and cornstarch. Pour them into a 8 or 9 inch casserole dish. Place the frozen crisp mixture on top of the peaches. I piled mine into a tall dome because I love crisp that much. Add three thinly sliced pieces of butter on top of the crisp.
Either place the casserole dish in a baking pan or line the shelf beneath the dish with tin foil to prevent it from bubbling over and getting in your oven.
Place in the oven for 50 to 55 minutes until golden brown and bubbly. Let cool.