Combine equal parts water and granulated sugar with 1 tablespoon brown sugar per cup of syrup in a small saucepan (for this recipe you need about 1/2 oz, so make 1/4–1/2 cup). Heat gently, stirring until sugar dissolves. Cool to room temperature and store in refrigerator. This step can be skipped if you have simple syrup ready.

Chill glass

Place a rocks glass or coupe in the freezer for a few minutes or fill it with ice water while you prepare the cocktail to ensure the drink stays cool.

Build and shake

Add 6 pieces of ice to a cocktail shaker. Pour in 2 oz Irish whiskey, 1 oz Irish cream liqueur, 1 oz heavy cream (or half-and-half), 1 oz cold brewed strong black tea or chilled espresso, 1/2 oz brown sugar simple syrup, 2 dashes Angostura bitters, and 1/4 tsp vanilla extract. Secure the shaker and shake vigorously for 12–15 seconds until the outside of the shaker is very cold and the cream is slightly frothy.

Prepare serving glass

Remove the chilled glass from the freezer or discard the ice water. Add crushed ice or a large ice cube to the serving glass.

Strain and present

Double-strain the shaken mixture into the prepared glass over the serving ice using a Hawthorne strainer and a fine mesh strainer to catch any small ice shards and cream solids. The drink should be silky and slightly frothy on top.

Garnish

Grate a small pinch of fresh nutmeg or dust with cocoa powder over the foam (about 1 tsp). Optionally express an orange twist over the drink to release oils, rim the glass with the twist, and drop it in as garnish.

Serve

Serve immediately while chilled. Encourage sipping slowly to enjoy the creaminess and layered flavors of whiskey, coffee/tea, and brown sugar.