Preheat the oven to 175°C
Mix together the flour, 100 ml of the sugar, cinnamon, milk and vanilla extract in a large bowl.
Add the pieces of butter and knead until a crumbly light mixture.
Place half of the crumble mixture in an oven-proof dish lined with baking parchment, and press out so that the dough sticks together.
Mix the berries with the lemon juice and the rest of the sugar, and spread over the pie base. If you use frozen berries, add 1.5 tbsp of potato starch.
Add the rest of the crumble mixture over the berries and carefully press the dough out slightly.
Bake in the oven for 30-35 min or until the top is a light brown colour.
Leave to cool then cut into squares.