Prepare the Dough
In a large mixing bowl, combine the all-purpose flour, whole wheat flour, sugar, and salt.
In a separate small bowl, dissolve the yeast in warm water and let it sit for 5 minutes until foamy.
Add the yeast mixture and warm milk to the dry ingredients and mix until a dough forms.
Cut the cold butter into small cubes and incorporate it into the dough, kneading until the butter is fully incorporated and the dough is smooth and elastic.
Cover the dough with plastic wrap and let it rest in a warm place for about 1 hour, or until doubled in size.
Shape the Gipfeli:
Once the dough has doubled in size, punch it down to release the air.
Divide the dough into equal portions and roll each portion into a ball.
Roll out each ball of dough into a thin circle, then cut it into triangles.
Place your desired filling (such as chocolate chips, almonds, or apricot jam) at the wide end of each triangle.
Roll up each triangle tightly, starting from the wide end and rolling towards the point to form a crescent shape.
Bake the Gipfeli:
Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
Place the shaped Gipfeli on the prepared baking sheet, leaving space between each one to allow for rising.
Bake in the preheated oven for 15-20 minutes, or until golden brown and flaky.
Remove from the oven and let cool slightly before serving.