Heat oven to 180C/fan 160C/gas 4. Butter and line the base of a 23cm square tin. For the crumble mix, put 2 tbsp flour and 25g of the butter with the demerara sugar and cinnamon in a bowl. Rub between your fingers until it resembles damp breadcrumbs.
Tip the remaining flour and butter and the caster sugar, eggs and vanilla in a bowl, then beat until well combined. Lightly fold in half the apricots and raspberries, then spread over the prepared tin.
Scatter over the remaining fruit, then sprinkle with the crumble mix. Bake for 45-50 mins until light golden, then cool for 10 mins and remove from the tin. Cut into squares and serve warm with cream or ice cream for dessert, or cold for tea.