|245 g||butter (divided)|
|340 g||confectioner’s sugar (divided)|
|1½ tsp||vanilla extract (divided)|
|flour for dusting|
In a large bowl beat butter until creamy, approx. 1 min with the hand mixer with beaters. Gradually add in confectioner’s sugar, cocoa, vanilla extract, and salt. Add flour and knead using your hands until dough is smooth.
Roll dough into an approx. 5-cm/2-in. thick log. Wrap in plastic and let chill in the fridge for approx. 30 min.
Preheat oven to 160°C/320°F. Cut log into an even number of slices. Transfer slices to a parchment paper-lined baking sheet and bake for approx. 10 min. Remove from oven and let cool completely.
In the meantime, prepare the filling. Add butter together with milk, vanilla extract, and confectioner’s sugar to a bowl and whisk to combine. Add the filling into a piping bag fitted with a decorating tip.