Add the 1 oz of chilled but unsweetened half and half in a cup.
Add one or more tablespoons of the simple syrup on the half and half and stir to combine them well.
In a separate cup, brew two shots of roast espresso. For balanced flavor, choose medium roast. Hold the back of a spoon over the cup containing half and a half and pour the espresso slowly over the spoon.
The coffee will rest on the half and a half giving you your sweet homemade Undertow.