Preheat your oven to 375°F (190°C). Lightly grease an 8x8-inch baking dish. 2. In a large bowl, toss the sliced peaches with granulated sugar, lemon juice, cornstarch, cinnamon, ginger, and salt until evenly coated. Let sit for 5 minutes while you make the topping. 3. In a separate medium bowl, whisk together the flour, oats, brown sugar, cinnamon, and salt. Add the cold butter cubes. Use a pastry cutter or your fingertips to work the butter into the dry mixture until it resembles coarse meal with some pea-sized butter pieces. Do not overwork; you want clumps. 4. Pour the peach mixture into the prepared dish, spreading evenly. Sprinkle the crumble topping evenly over the peaches, covering completely. 5. Bake for 30-35 minutes, until the filling is bubbly around the edges and the topping is golden brown and crisp. If the topping browns too quickly, tent loosely with foil after 20 minutes. 6. Let cool on a wire rack for at least 15 minutes before serving. The filling will set as it cools. Serve warm, optionally with vanilla ice cream or whipped cream.