Mix the dry ingredients together: all-purpose flour, almond flour, sugar, baking powder, and salt.
Cut in the cold butter using a pastry cutter or grater until the mixture resembles coarse crumbs.
In a separate bowl, whisk together heavy cream, egg, and almond extract. Pour into dry mixture and stir until combined.
Fold in the sliced almonds. Turn dough onto a floured surface and shape into a disk. Chill for 15 minutes.
Cut into 8 wedges, place on parchment-lined baking sheet. Brush with cream, sprinkle coarse sugar and extra almonds.
Bake at 400°F (200°C) for 18–20 minutes or until golden. Cool on wire rack before serving.