Don't let a lack of nutmeg keep you from making a recipe. Here are several suitable substitutes:
Best Bet: Mace. It's the outer membrane that surrounds nutmeg before it is harvested, so it shares a lot of the same flavors. Replace the nutmeg in your recipe with an equal amount of mace.
Still Good: Cinnamon, allspice, ginger or ground cloves. Replace measure for measure.

