In a large mixing bowl, combine the softened butter, powdered sugar, vanilla sugar, and salt. Blend until smooth and creamy. Gradually add eggs, mixing well after each addition. Incorporate flour and baking powder until fully combined. Knead briefly, then divide into three equal portions and shape into balls.

Take one portion of the dough, mix in ground pistachios and lemon zest until evenly distributed. Roll out to about ½ cm thickness. Use cookie cutters for fun shapes, arrange on a baking sheet and set aside.

For the second portion, mix in cocoa powder thoroughly. Shape into small balls weighing about 20 g, then roll into sticks approximately 8 cm long. Place on a baking sheet.

Keep the third portion plain, shape into balls approximately 18 g each, dip in egg white, then roll in chopped peanuts. Press into the center to create a well for the jam.

For the jam filling, combine strawberry jam and granulated sugar in a saucepan over medium-low heat. Stir until bubbling and sugar dissolves. Cool slightly and transfer to a piping bag.

Preheat oven to 190 °C (375 °F). Bake all cookie varieties for about 10–15 minutes, until lightly golden. Allow cookies to cool before filling thumbprint cookies with jam.

Melt the white chocolate, dip half of pistachio-lemon cookies into it, drizzle remaining chocolate over the tops and garnish with chopped pistachios and optional rose petals. Melt the milk chocolate with sunflower oil, mix in chopped hazelnuts, and dip chocolate sticks into the mixture.