Grab a rocks glass and pour in the peanut butter whiskey. While there are other brands of peanut butter whiskey, Skrewball is the most popular.
Add a few dashes of angostura bitters to the peanut butter whiskey. You don't need a lot -- a few dashes does the trick.
Now add a large ice cube to the glass. Stir it to chill the drink and slightly melt the ice for a touch of dilution.
When you need the ultimate cocktail for peanut butter lovers, look no further. This Skrewball old fashioned always hits the spot.