Caffè shakerato

For ➊ glass
6-8 ice cubes
1-2 ts simple syrup**, or to taste
1 dash liqueur, such as rum, sambuca, or Amaretto (optional)
2 shots freshly made, hot espresso

In a cocktail shaker*, add the ice cubes, simple syrup, liqueur**** (if using), then finally the freshly made espresso. Put the lid on and shake vigorously for 10 to 15 s. The shaker should become ice cold and the mixture should become a light caramel-colored froth. 
Strain the liquid into a chilled martini glass, ensuring no ice cubes end up in the drink.
If desired, garnish with a coffee bean or a dusting of cocoa powder—or go for it and top with whipped cream.

*If you don't have a cocktail shaker, improvise with a jar with a screw top lid. You can also make this in a blender and you'll end up with a super frothy cocktail-like drink that will feel like you're drinking a caffeinated cloud.
**Boil one part sugar with one part water in a small saucepan until the sugar dissolves. Store in a jar in the refrigerator for a week.
***Spice things up by spiking the coffee with a dash of something alcoholic. Try rum, sambuca, or amaretto. Or add some vanilla extract or a twist of lemon zest for something different.
Add it to the shaker before the hot coffee, which must always come last.