Rub the butter with the raw cane sugar with the tip of your fingers.

Mix in the beaten egg. Sift plain flour and spelt flour with salt and baking powder, then rub them in with lemon zest.

Knead into a ball, flatten it a little bit, wrap in cling film and let it rest in the fridge for a few hours, or overnight.

Heat oven to 180°C.

Remove the pastry from the fridge, halve the ball and knead it, then roll out on a floured surface with a rolling pin.

Roll out the pastry on the bottom of a 26 cm round cake tin.

Spread the blackberry jam on the bottom of the crostata, then add the strawberries, cut into small pieces.

Use the left pastry to decorate the crostata with intertwined strips.

Bake the cake for about 30 minutes, until golden brown Let cool before serving.