In a mixing bowl, combine flour, sugar, salt, and yeast.
Add cold butter cut into small cubes and mix until crumbly.
Pour in warm milk and mix until a dough forms.
Knead the dough on a floured surface for about 5 minutes.
Wrap the dough in plastic wrap and refrigerate for 30 minutes.
Roll out the dough into a rectangle on a floured surface.
Fold the dough into thirds and refrigerate for another 30 minutes.
Roll out the dough again and cut into triangles.
Place chocolate chips at the wide end of each triangle.
Roll the triangles tightly and place them on a baking sheet lined with parchment paper.
Brush with beaten egg and let rise for 30 minutes.
Bake in a preheated oven at 400°F (200°C) for 20-25 minutes.