1. Add the flour, sugar, baking powder, and salt to a large bowl and mix to combine. Add the vanilla extract, the butter in small pieces, and the egg and knead until you get a nice and smooth dough. Shape into a ball, flatten that ball, and wrap it in plastic wrap. Place in the fridge for about 1 hour.

2. While the dough is resting in the fridge prepare the streusel topping. Combine the flour and brown sugar in a bowl, add the butter, vanilla extract, and salt and mix with a fork or your fingers until different-sized streusel form. Place in the fridge until needed.

3. Preheat the oven to 180°C (350°F). Lightly grease a 10 inches (26cm) springform tin and line with a piece of baking parchment. Roll out the dough on a lightly floured surface slightly larger than the springform tin. Transfer to the tin and press to the bottom and sides – the rim should be at least 1.2 inches (3cm) high. Prick the bottom several times with a fork and place in the fridge until needed.

4. For the filling, peel the apples, quarter, and remove the core. Cut the pieces once again in half lengthwise and then into slices crosswise. Add to a bowl and mix with the lemon juice. Mix the brown sugar and cinnamon, sprinkle over the apple pieces and mix well. Pour the apple mix into the prepared crust and sprinkle with the streusel. Bake for about 55-60 minutes – the edge and crumbles should have a nice golden color. Take out of the oven and let cool down completely inside the springform tin. When cooled remove carefully from the tin and serve with some whipped cream or vanilla sauce.