Process hazelnuts in a food processor until a powder forms.
In a mixing bowl, sift the flour and baking powder. Whisk in cane sugar, vegan egg, coffee extract, ground coffee, and vanilla sugar. Rub in vegan butter until smooth.
Shape the dough into a disc, wrap and chill for 2 hours.
Preheat the oven.Roll out the dough between two sheets of waxed parchment paper. Cut out cookies with a cookie cutter.
Bake for 15-20 minutes (365F), until nicely colored.Brush and fill cookies with a warm jam .