Preheat the oven to 180°C (356°F).
Roughly chop the walnuts.
In a large bowl, mix together whole wheat flour, baking powder, salt, and cinnamon.
Add the cold butter and mix with your hands or a mixer until crumbly.
Add sugar and chopped walnuts, and mix to combine.
Add milk and egg to complete the dough.
Roll out the dough to 2–3 cm thickness and cut into triangles.
Place on a baking pan and lightly brush the tops with milk.
Bake in the oven for 20–25 minutes.