With an electric mixer, beat the butter and sugar until light and fluffy. Add the eggs one at a time, and beat well. Add the brandy or vanilla. Stir in the melted chocolate and the sour cream.
Whisk all the dry ingredients together in a separate bowl, then add to the batter, stirring until blended. You can do this by hand or using low speed of a mixer.
Stir in the chocolate chips and the nuts. Drop dough by tablespoonfuls onto parchment lined baking sheets.
Bake for about 12 minutes. If making the cookies larger, you'll need to bake for about 15 minutes. Do not over-bake.
Notes
Makes approximately 48 cookies, but you can make up to 60 if you make them very small. You can also make as few as 20 if you want monster size cookies.