In the bowl of a stand mixer fitted with the paddle attachment, combine butter and sugar. Add flour, salt, vanilla extract, egg yolks, ground almonds, cinnamon, and lemon peel. Mix until a smooth dough forms. Wrap dough in plastic wrap and chill in the fridge for at least an hour.

Take dough out of the fridge and shortly knead by hand.

On a floured work surface, roll out the dough. It should be 0.2 inches (5mm) high. Use a cookie cutter to cut out circles or hearts. Transfer cut out cookies to a baking sheet covered with parchment paper. Use a smaller cookie cutter to cut out a small hole or shape of half the cookies. Chill cookies on baking sheet for 30 minutes.

Preheat oven to 350F (177C). Bake cookies for 8-12 minutes in the middle of the oven until edges are lightly browned. Transfer cookies to a cooling rack and let cool completely.

To decorate the cookies, sprinkle the cookies with holes with powdered sugar. Brush the tops of the cookies that don’t have a hole with jam and put one of the other cookies on top. Let the cookies dry on the cooling rack for about 2 hours then transfer to cookies tins. Store in a dry and cool place.