Preheat oven to 350F and grease two baking trays with butter.

In a bowl combine softened butter and sugar, cream together until well combined.

Add in egg yolks, salt and vanilla extract, stir well. Add in flour. Mix for a few minutes, dough will come together.

Separate dough in equal measurements to 4 bowls, add 2 drops of food coloring to each bowl and mix with dough until your desired shade.

Scoop dough into 1 tbsp size balls, roll in sugar and then place on your baking tray. Repeat with rest of the dough.

Then using either the end of a large wooden spoon or your thumb, press an indentation into each cookie.

Bake for 12-15 min or until the bottoms are lightly browned and the cookies are set. Mine took 13 min.

Transfer to a wire rack and cool.

While cookies are cooling in a pot melt chocolate chips along with coconut oil, fill in each cookie indentation with chocolate. Let sit for another 5 minutes or until chocolate solidifies a tad.

ENJOY :)

Keep for up to a week in an airtight container