Step 1: Preparing the Dough

1. Warm the milk to about 38°C (100°F). Add the sugar and yeast, stir, and let sit for 5–10 minutes until frothy.
2. In a large bowl, whisk together the flour and salt.
3. Pour in the yeast mixture and knead until a smooth, elastic dough forms (about 8–10 minutes).
4. Cover the dough with a damp towel and let it rise in a warm place for about 1 hour, or until doubled in size.

Step 2: Laminating the Butter

5. Place the cold butter between two sheets of parchment paper and roll it into a 20x20cm (8×8-inch) square. Refrigerate for 15 minutes.
6. Roll the dough into a rectangle about twice the size of the butter slab.
7. Place the butter in the center of the dough and fold the dough over it, sealing the edges.
8. Roll the dough into a long rectangle and fold it into thirds (like a letter).
9. Chill for 30 minutes, then repeat the rolling and folding process two more times to create layers.

Step 3: Shaping the Gipfeli

10. Roll out the chilled dough into a large sheet about 5mm (¼ inch) thick.
11. Using a sharp knife or pizza cutter, slice the dough into long triangles with a 6cm (2.5-inch) base and a 15cm (6-inch) height.
12. Starting from the base, roll each triangle into a crescent shape, stretching slightly as you roll.
13. Place the shaped Gipfeli on a parchment-lined baking sheet, spacing them 5cm (2 inches) apart.

Step 4: Proofing and Baking

14. Cover the pastries with a clean kitchen towel and let them proof at room temperature for 30–45 minutes.
15. Preheat the oven to 200°C (392°F).
16. Whisk together the egg and milk, then lightly brush the Gipfeli with the egg wash.
17. Bake for 15–18 minutes, or until golden brown.
18. Transfer to a wire rack and allow to cool for at least 10 minutes before serving.