01 -
Combine all-purpose flour, baking powder, and powdered sugar in a mixing bowl. Melt the butter in a microwave or on the stovetop, then add it and the vanilla extract to the dry ingredients. Mix until smooth. Chill the dough in the refrigerator for 30 minutes.
02 -
Wash, drain, and weigh the mulberries. Process them in a food processor for one minute, then transfer to a pot. Add sugar equal to half of the mulberries' weight. Cook over medium-high heat until boiling, then reduce heat to medium-low and simmer until the juice reduces by half. Add the juice of half a lemon and 4-5 lemon seeds. Cook until the jam thickens.
03 -
Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper. Shape tablespoons of dough into balls, placing them on the baking sheet. Press your thumb into the center of each ball to create a nest.
04 -
Add about 1 teaspoon of mulberry jam into the center of each cookie. Avoid overfilling to prevent spillage during baking.
05 -
Bake the cookies in the preheated oven for 12-15 minutes or until golden. Let them rest for a couple of minutes before transferring to a cooling rack.