Beat the butter alone so that it becomes very creamy. Then add the brown sugar and beat again for a few minutes. Then add the egg, salt and vanilla and mix.
Separately, mix together the flour and ground almonds then pour into the dough. Mix to incorporate everything. At this stage the dough is wet and this is normal. Form a slightly flat dough and wrap it in cling film. Refrigerate at least 1 hour (up to 2 days maximum).
Preheat the oven to 175 ° traditional heat. Line several baking sheets with parchment paper.
Between two sheets of baking paper, roll out the dough with a rolling pin to obtain a dough height of approximately 0,5cm. With your cookie cutter (mine is 6cm), make as many cookies as possible. On half of them, make a hole in the middle with a smaller cookie cutter (of a different shape).
Arrange the cookies on a baking sheet, spacing them out, then bake for about 10-13 minutes, depending on their size. They should not be too golden, and keep a light color. Out of the oven, let cool on a baking sheet then transfer to a rack until completely cooled.
Garnish whole cookies with jam. Sprinkle those with a hole with icing sugar then place them on the jam part, pressing lightly.
Notes
These cookies can be stored in an airtight container at room temperature for up to a week.