In a mixing bowl, cream the softened unsalted butter with powdered sugar, fine salt, and vanilla extract until pale and fluffy, about 3-5 minutes.

Gradually sift in the all-purpose flour and Dutch processed cocoa powder, stirring gently until a soft, smooth dough forms.

If the dough feels too soft, chill it in the refrigerator for about 30 minutes.

Slice and Bake: Press the dough into a greased and lined baking tray, score into bars, and bake at 150°C (300°F) for 20 minutes.

Log Method: Roll the dough into a log shape, wrap in plastic wrap, chill for 1-2 hours, cut, and bake until lightly golden.

Rolled Cookies: Roll out the dough on a floured surface, chill, cut with cookie cutters, and bake until set.

Allow the biscuits to cool completely on a wire rack after baking.

Melt the dark cooking chocolate and gently coat each biscuit as desired, then let the chocolate set on parchment paper.