Preheat the oven to 375F. In a bowl, combine the sliced peaches, lemon juice, and vanilla extract.
Add sugar, flour, cinnamon, and salt. Stir to combine. Grease a 9x13 baking dish with non-stick cooking spray or butter. Transfer the peaches to the prepared baking dish. Set aside.
In another bowl, combine the flour, rolled oats, granulated sugar, brown sugar, cinnamon, nutmeg, and salt.
Cut the cold butter into the flour mixture using a fork, pastry blender, or with your hands.
Sprinkle the topping over the peaches and bake for 30-40 minutes or until golden brown and bubbly. Let it cool for 10-15 minutes, and serve with a scoop of vanilla ice cream on top.