2) Pour the ginger simple syrup into a blender and puree. Strain out the pulp and store in a tightly sealed jar or bottle. Will keep for several weeks in the refrigerator.
For the margarita:
1) Pour some bar sugar onto a small plate and grate a pinch of nutmeg on top, then mix well.
2) Add the tequila, lime juice, 150ml of the ginger simple syrup and ice to a cocktail shaker and give it a good shake.
3) Run a lime wedge around the rim of the glass and dip in the sugar/nutmeg mixture to coat the rim.
4) Add ice to the glass and pour in the contents of the shaker. Grate a little nutmeg on top and serve with a wedge of lime.