Preheat oven to 350°F. Spray a 9 x 9-inch baking dish with cooking spray and set aside.
In a large bowl, combine sliced peaches with the flour, sugar, corn starch, and vanilla. Gently stir and pour into prepared dish.
In a separate large bowl, combine the oats, brown sugar, flour, salt, and cinnamon. Stir until well combined and the brown sugar clumps are broken down. Add the butter pieces and mix in with your hands until you have a crumbly mixture. Stir in the chopped almonds. Evenly sprinkle the crisp topping over peaches.
Bake for 30-35 minutes until the topping is golden brown and the crisp is bubbling. Remove from the oven, place on a wire rack, and cool for 15 minutes before serving. Serve with ice cream, if desired.
The crisp is best the day it is made, but will keep in the refrigerator for up to 2 days. Reheat before serving.