1) In a large bowl, cream together the butter and sugar, add the egg, vanilla and lemon zest and using a handheld electric whisk, whisk for a few minutes or until the mixture becomes thick and takes on a consistency similar to a mousse. 2) Add the ground almonds and flour and mix until you have a creamy mixture. Pop it in the fridge to set for about 15 minutes.3) Preheat your oven to 400 degrees, line two baking sheets with some parchment paper and set aside.3) Roll out a sheet of puff pastry on a lightly floured surface, roll it out so it’s about 1/2” bigger on all 4 sides. 5) Cut 4 large rounds out of the puff pastry and place them on your prepared baking sheet. Quickly toss the apples with the 2 tablespoons of sugar and set them aside.6) Add a dollop of the almond mixture in the center of each circle and spread it around a bit making sure to leave a little border, arrange a few apple slices on top of the mixture and sprinkle over a few sliced almonds. 7) Continue with the rest of the filling and pastry, then pop them in the oven and allow them to bake for about 20 minutes or until golden brown. 8) Sprinkle them with some powdered sugar and serve right away!