Knead together the grated almonds, brown sugar, cinnamon, egg yolk, and 1 tablespoon cream or condensed milk into a smooth dough. Let rest at room temperature for 4 to 5 hours.
Roll out the dough using ground almonds or sugar to prevent sticking. Cut out star shapes of any size.
Place the stars on a baking sheet lined with baking paper. Bake in a preheated oven at 180 °C / 356 °F with top and bottom heat for 10 to 12 minutes.
Cool completely on the baking sheet.
Mix the 25 g powdered sugar with 1 teaspoon cream or condensed milk to make a glaze. Coat the top of each cinnamon star with the glaze.