Preheat oven to 350°F. Butter or spray a 9” x 9” baking dish.
Drain the peaches in a colander to remove excess liquid. Place the peaches in the prepared baking dish.
In a small bowl, combine the brown sugar, oatmeal and flour. Add the butter and pinch to combine with the dry ingredients until the mixture is crumbly. Take some of the topping in your hand and squeeze so that it comes together, then crumble over the top of the peaches. Repeat until all the topping is used. Bake until the top is golden and the peaches are bubbling, about 40 minutes. Let cool at least 10 minutes before serving.
