Preheat your oven to 375°F and grease a 9 inch baking dish with butter or baking spray. Place peeled and slicedpeaches in the baking dish after greasing.
Add boxed cake mix to the bowl of a food processor with cold cubed butter pieces and lemon zest, if using. Pulse to create a crumb texture. If you don’t have a food processor, you can use a pastry cutter, 2 knives, or your clean hands to cut the butter into the cake mix.Pour the crumbs over the top of the peaches in the baking dish.
Sprinkle the crumbs over the top of the peaches in the baking dish and spread to cover them evenly. Bake for 30-40 minutes until the top is golden. Serve with ice cream and fresh peach slices, and enjoy!
Lemon zest is optional but highly recommended. I love the tiny bit of tang it adds to the end result. It really brightens up the flavor!