Preheat your oven to 350°F (175°C) and lightly grease your baking dish.
In a large mixing bowl, gently toss the sliced peaches with granulated sugar, lemon juice, and cinnamon until evenly coated. The peaches should look glossy and start releasing their juices.
Spread the peach mixture evenly in your prepared baking dish, creating a generous layer of fruit that looks juicy and inviting.
In a separate bowl, combine the flour, oats, brown sugar, and salt. Mix until well combined; the mixture should be crumbly and slightly coarse.
Add the cold, cubed butter to the dry ingredients. Use your fingers or a pastry cutter to blend until the mixture resembles coarse crumbs with some larger clumps. This will create a flaky, buttery topping.
Sprinkle the crumble evenly over the peaches, covering the filling completely with a thick, textured layer of topping.
Bake in the preheated oven for about 40 minutes, until the topping is golden brown and crisp, and the filling is bubbling around the edges.
Remove the dish from the oven and let it cool slightly until it sets up a bit, but still remains warm and inviting.
Serve the peach crisp warm, ideally with a scoop of vanilla ice cream or a dollop of whipped cream for extra indulgence.
