Brew 200 ml of strong coffee using your preferred method (French press, espresso machine, or drip coffee maker).
In a saucepan, heat 50 ml of milk over medium heat until it is steaming but not boiling.
Add 1 teaspoon of hazelnut syrup to the heated milk and stir well to combine.
Pour the brewed coffee into a cup, and then slowly pour the hazelnut milk mixture into the coffee, stirring gently.
If desired, top the hazelnut coffee with a dollop of whipped cream and a sprinkle of crushed hazelnuts.