1. *Make the tart* Process flour, almond powder, sugar, butter and egg yolk in a food processor for a few seconds until mixture becomes crumbly : do not process too much as the dough should be crumbly.
2. Transfer the dough onto a work surface. Gather it into a ball shape of dough with your hands. Gently flatten the ball into a disk shape and wrap it in plastic wrap. Refrigerate for at least 30min.
3. *Roll the dough* Put a plastic wrap covering on your work surface, place the dough on it. Then cover with another piece of plastic wrap. Let it sit for a few min to soften slightly. Roll the dough out into a circle bigger than your tart mold. Take off from the bottom wrap and place gently into your tart mold (or ring). Using a sharp knife, trim the edges of the pastry to fit the tart pan. Take off the top wrap and prick bottom and side of tart thoroughly with a fork. Put it in the refrigerator or freezer until firm (about 30min).
4. *Almond filling* In a medium bowl, stir together the butter and sugar until smooth. Add beaten egg and mix. Finally add the almond flour and mix well until fluffy and thoroughly combined.
5. *Assemble* Spread the almond filling into the tart crust. Then arrange the pear slices and apple slices over the almond filling. Dot the top of the tart with tiny bits of butter, then sprinkle sugar as much as you want. Pre-heat the oven to 180℃.
6. Bake the tart for about 50~60min or until the top is nicely browned. Remove from the oven and let it to cool to room temperature.