1. Preheat the oven to 400°F and grease two 9½-inch round porcelain baking dishes with melted butter. Wash and dry all the fruit, and then hull the strawberries and pull the red currants off their stalks.
2. Put the berries and currants in a large bowl, sprinkle with a scant ½ cup of the sugar, and stir to combine. Divide the fruit between the baking dishes, spreading it in a single layer.
3. In a separate large bowl, combine the flour, cinnamon, remaining sugar, diced butter, and ground almonds. Rub the ingredients lightly together with your fingertips until coarse crumbs form.
4. Scatter a layer of the crumb mixture over the fruit in the baking dishes and bake for 40 minutes, until the topping is golden and crisp. Serve warm.