Easy Blackberry Traybake

Preheat the oven to 180 °C (160 °fan/ Gas 4/ 350 °F) and grease and line a 30 x 20cm (12 x 8 inch) baking tin.
Put the plain flour, oats and light brown sugar in a large mixing bowl and rub in the cubed butter until fine crumbs form.
250 g Plain Flour, 25 g Oats, 250 g Light Brown Sugar, 200 g Butter
Stir in the desiccated coconut, then set aside one cupful of the mixture for the topping (a teacup works perfectly).
80 g Desiccated Coconut
Mix in the eggs, lemon zest, and chopped walnuts to the mixing bowl. The mixture will be sticky and dense.
2 Eggs, 1 Lemon, 50 g Walnuts
Press the cake mixture into the prepared tin. Use the back of a spoon to ease it into all of the corners.
Scatter over the blackberries and lightly press down.
300 g Blackberries
Sprinkle over the reserved topping and bake in the oven for 1 hour until lightly golden. Allow to cool before cutting into squares.