Process the walnuts into granular form in a processor.
In a mixing bowl, whisk together the eggs, sambuca, and granulated sugar. Add the walnuts.
Melt the butter and chocolate (I use a Pyrex cup in the microwave, but you can also use a stovetop). Add this to the mixing bowl and combine well.
Mix in the all purpose flour, salt, and baking powder.
Let the dough sit at room temperature, covered, for about 1 hour, until it hardens enough to shape.
Pre-heat the oven to 350˚F. Shape the dough into cookie balls and roll in powdered sugar. They will not expand much in the oven, so you can place them relatively close together on the baking pan.
Bake at 350˚F for 8-10 minutes, until cracked on top. Let sit 1 minute on the pan, then remove and enjoy!