Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, combine the ground almonds, powdered sugar, salt, and baking powder. Mix well until all dry ingredients are evenly distributed.

In a separate bowl, whisk the egg whites until they are frothy but not stiff. Add the vanilla extract to the egg whites and mix to combine.

Gradually add the egg white mixture to the dry ingredients, stirring gently until a dough forms. The dough should be slightly sticky and hold together.

Using your hands, form small balls of dough, about 1 inch in diameter. Place them on the prepared baking sheet, leaving space between each cookie.

Gently press a slivered almond onto the top of each cookie for decoration.

Bake in the preheated oven for 15-20 minutes, or until the cookies are lightly golden around the edges. Keep an eye on them to avoid over-baking.

Once baked, remove the cookies from the oven and let them cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.

Enjoy your Ghriba cookies with a cup of tea or coffee!