Pull two shots of espresso (about 2 ounces) directly into a 12-ounce mug.

Add 1 to 1.5 tablespoons of hazelnut syrup to the hot espresso and stir until fully combined.

Pour 8 to 10 ounces of cold whole milk into a milk pitcher until it is about one-third full.

Position the steam wand just below the surface of the milk and turn on the steam to high to begin aeration.

Allow the steam wand to remain near the surface for about 2 seconds to introduce air, then submerge it deeper to create silky microfoam (about 30 seconds).

Continue steaming until the milk temperature reaches 150 to 155 degrees Fahrenheit (about 45 seconds total). Turn off the steam immediately.

Purge the steam wand over a sink for one second and wipe it with a damp cloth to clean any milk residue.

Pour the steamed milk into the espresso and hazelnut syrup mixture, holding back the microfoam with a spoon until the cup is three-quarters full, then top with a layer of microfoam.

Dust the microfoam with hazelnut powder or cocoa powder if desired and serve immediately.