Preheat the oven to 350°F (175°C).
In a mixing bowl, combine the cranberries, granulated sugar, 1 tablespoon of flour, cinnamon, and lemon juice. Stir well to coat the cranberries. Pour this mixture into the pie dish.
In another bowl, mix 1 cup of flour, rolled oats, brown sugar, and a pinch of salt. Add the cold cubed butter and use a fork or pastry cutter to blend until the mixture resembles coarse crumbs.
Evenly sprinkle the crumble topping over the cranberry mixture in the pie dish.
Place the pie dish on a baking sheet to catch any drips. Bake in the preheated oven for about 45 minutes, or until the topping is golden brown and the cranberries are bubbly.
Remove from the oven and allow to cool for about 10 minutes before serving.
Serve warm, optionally with vanilla ice cream or whipped cream for an extra treat.