Melt butter in pan over low heat.
Add cocoa and stir till smooth.
Add in condensed milk and stir constantly until thick, smooth, and glossy (about 4 minutes).
Remove from heat and pour in vanilla and Amaretto. Stir to combine.
Refrigerate for 3-4 hours or until firm.
Shape into 1-inch balls with a cookie scoop or your hands and roll in cocoa powder.
Chill until firm 1-2 hours.
Store in airtight container in fridge.