In a large mixing bowl, beat 540 g of softened butter with 150 g of powdered sugar, 8 g of vanilla sugar, and 4 g of salt until smooth and creamy. Add in 3 eggs, one at a time, mixing well after each addition. Gradually incorporate 600 g of all-purpose flour and 10 g of baking powder, kneading until the dough is well combined and forms a cohesive ball. Divide the dough into three equal portions, roughly 540 g each.

Take one portion of the dough and mix in 100 g of ground pistachios and the zest of 1 lemon until evenly distributed. Roll the colored dough out to about ½ cm thick on a floured surface. Use cookie cutters to cut out your favorite shapes, and carefully place them on a parchment-lined baking sheet. Set aside while you prepare the next cookie variety.

For the second portion of the dough, add 50 g of cocoa powder and mix thoroughly until the chocolate is fully incorporated. Shape the dough into small balls, approximately 20 g each, then roll them into sticks about 8 cm long. Place these chocolate sticks onto another parchment-lined baking sheet, ensuring they are spaced apart for even baking, and prepare for the next cookie variety.

Using the last portion of dough, shape it into balls weighing about 18 g each. Flatten each ball slightly, dip it in egg white, and roll it in chopped peanuts, making sure they are well-coated. Use your finger to create a deep well in the center of each cookie. Arrange these cookies on the baking sheet, ensuring they have enough space as they will expand during baking.

In a small saucepan, mix 400 g of strawberry jam with 50 g of granulated sugar over medium-low heat. Stir continuously until the mixture begins to bubble and the sugar dissolves completely, allowing the flavors to meld together. Once ready, remove from heat and let cool briefly before transferring the filling to a piping bag for easy use later.

Preheat your oven to 190 °C (375 °F) while you prepare the cookies. Place all the cookies in the oven and bake for about 10–15 minutes, monitoring closely as baking times may vary based on your oven. The cookies should be lightly golden and firm around the edges. After baking, allow them to cool on the baking sheets for a few minutes before transferring to a wire rack.

Once the peanut thumbprint cookies have cooled, use the piping bag to fill each well with the prepared strawberry jam. This delightful filling adds a sweet surprise to every bite! Set these aside while you prepare the decorations for the other cookies.

In a double boiler, melt 80 g of white chocolate. Once melted, dip half of each pistachio-lemon cookie into the white chocolate, allowing the excess to drip off, then place them on parchment paper. With any leftover white chocolate, pipe decorative stripes on top and finish with a sprinkle of chopped pistachios and optional rose petals for a lovely touch.

Melt 50 g of milk chocolate with 10 g of sunflower oil, stirring until smooth. Dip each chocolate stick into the mixture, coating well before letting the excess drip off. Place them back onto the parchment-lined baking sheet, allowing the chocolate to set. Enjoy the delightful varieties created from your Three Cookies from One Dough!