Preheat oven to 180 °C (350°F) conventional and line two large baking sheets with parchment paper.
Combine flour and salt and mix until well combined. Set aside.
In a large bowl combine softened butter and sugar and cream for 3 minutes until light and fluffy.
Add in egg yolks, vanilla and milk powder and mix on a low speed until well combined.
Add in premixed dry ingredients and mix on low-medium speed until just combined.
Use a spatula to gently press down on the dough to release any air bubbles, then mix carefully until the dough is smooth.
Transfer half of the dough into a large piping bag and pipe the dough into small rosettes onto the parchment-lined baking sheets.
Place cookies into the fridge to chill for 30 minutes.
Bake one tray at a time on the middle rack of the oven for about 15 minutes, or until the cookies begin to develop a light golden brown color.
Once baked, let the cookies cool on the tray for 30 minutes to firm up.
If coating with chocolate, melt the chocolate and dip each cookie halfway into the melted chocolate, then place it back onto the parchment paper to set.
