- 2 sticks (225g) Unsalted butter
- 3/4 cup Sugar
- 1–2 Vanilla bean(s)
- 1 cup All-purpose flour
- 1 cup Whole-wheat flour
- 1 tsp. Baking soda
- 1/8 tsp. Salt
- 1/3 cup Preserves (I recommend Boysenberry, but pick your favorite or mix it up)
- Melt the butter over medium heat, stirring occasionally, until you see hazelnut brown flecks at the bottom of the, by then translucent, butter. This step is key to the taste, so make sure you wait for the brown flecks. Then, put the pan in water to stop the cooking. Stir for a minute to cool the butter.
- Use a sharp knife to split the vanilla bean(s) and scrape out the seeds; mix these with the sugar. In a medium bowl, mix the flours, baking soda, and salt. Stir the sugar / vanilla mixture into the warm (not hot) butter. After it is integrated, add the flour mixture. This may take a while as the butter will need time to provide moisture to the flour. Initially, it is a dry dough. Cover the dough and let it rest for 2–8 hours.
- Preheat the oven to 325°F / 165°C. Using a dough scraper, split the dough into 128 roughly equal sized balls: 1) Split the dough in half; 2) Split each of those in quarters; 3) Split each of those in quarters; 4) Split each of those in quarters. The balls should be roughly the size of a standard marble. Put them on a non-sticking cookie sheet and flatten them with your fingers. Bake for 10–12 minutes. Take out of the oven. After 5 minutes, move them to a cooling rack and leave them there overnight.
- The next day, assemble the cookies. In a small sauce pan, heat up the preserves to liquify them. If your preserves have seeds, press them through a metal sieve to remove the seeds. Put a small bit of the preserves between two halves to make the cookie and put back on the cooling rack. The following day, move the cookies to an airtight container, where they can be kept up to two weeks. While the cookies are good to begin with, they actually achieve optimal taste and texture 5 days after baking.