Just mentioning the three words -- hot fudge sauce -- brings a tumble of childhood memories, many centered on lazy summer ...

Melt butter or margarine with chocolate over lightly boiling water. Mix in sugar and milk. When combined, add vanilla. To prevent grainy texture, be sure to heat sufficiently so sugar crystals melt.

This will take between 2 to 4 minutes, depending on your speed and strength. Use the sauce immediately.