- Combine brown sugar, salt, vanilla extract, butter, milk, and rum in a saucepan. Stir to a boil and remove from heat. Whisk in milk chocolate and allow to cool at room temperature.
- Add powdered sugar in 1/2 cup amounts stirring mixture smooth between additions. If batter becomes too firm, transfer on a board dusted with powdered sugar and mix by hand.
- The batter will set and become firmer in 10-20 minutes. Shape in 1-inch round balls and roll in chopped nuts.
- Place on parchment or wax paper and store in refrigerator.