The “blood rim” is made from the same kind of sauce as you’d use to make candy apples. It’s actually really easy, but you’ll need a candy thermometer (which you can get at most grocery stores). Here’s the recipe:

1 c. Sugar
1/2 c. Karo Syrup
1/2 c. Water
Red Food Coloring
Cinnamon (optional)

Combine sugar, syrup and water. Cook without stirring to hard crack stage – which is 300 degrees F. Add food coloring. Cinnamon may be added for flavor.

Turn off heat. While the mixture is still hot, dunk the top of the cocktail glass into the mixture to create the red rim.

The thick consistency of the mixture will cause “drips” as it cools and hardens on the glass!