Preheat your oven to 350°F (180°C) and line an 8-inch square baking pan with parchment paper.

In a large mixing bowl, combine all-purpose flour, oats, dark brown sugar, and sliced almonds, then cut in the cold unsalted butter until resembling coarse crumbs.

Press half of the crumble mixture into the bottom of the prepared baking pan and bake for about 15 minutes until just starting to set.

In a separate bowl, gently toss the sliced peaches and raspberries with lemon juice and vanilla extract.

In another bowl, whisk together flour, granulated sugar, and salt, then sprinkle over the fruit mixture.

Layer the fruit mixture over the baked crumble base and sprinkle the remaining crumble on top.

Bake for an additional 35-40 minutes until golden brown and the fruit bubbles.

Let cool completely in the pan for 30 minutes before lifting out and slicing into squares.