- 1/2 cup all-purpose flour, spooned and leveled
- 1/2 cup old-fashioned rolled oats
- 5 tablespoons unsalted butter, at room temperature
- 1/3 cup light brown sugar
- 1/2 teaspoon cinnamon
- 1/4 teaspoon plus a pinch fine sea salt or table salt
- 1/2 pint blackberries
- 1 tablespoon granulated sugar
- 2 plums, pitted and sliced
- 2 teaspoons fresh lemon juice
- 1 pint vanilla ice cream
- Heat oven to 350° F. Mix together the flour, oats, butter, brown sugar, cinnamon, and ¼ teaspoon of the salt in a medium bowl. Transfer to a rimmed baking sheet and, using your hands, form the mixture into large clumps. Freeze until hard, 15 to 20 minutes.
- Bake the crumble until golden brown, 20 to 25 minutes. Let cool.
- Meanwhile, mash the blackberries and granulated sugar in a medium bowl. Add the plums, lemon juice, and the remaining pinch of salt and mix to combine.
- Divide the ice cream, fruit and juices, and crumble among 4 glasses or bowls. Serve immediately.