Combine the nutmeg, cardamom, cloves, ginger and cinnamon and set aside.
Place the egg whites and sugar in a heat proof bowl. We prefer to use the metal bowl of our stand mixer.
Fill a pot smaller than your bowl with a couple inches of water and bring to a boil. Once boiling turn down to a simmer and set the bowl on the pot to create a double boiler. Continuously stir the egg whites and sugar until the sugar has fully dissolved or the temperature reaches 160 degrees on a candy thermometer.
Transfer the bowl to a stand mixer fitter with the whisk attachment and mix on high until the mixture holds stiff peaks, about 8-10 minutes.
While the meringue is mixing cut the butter into 1 inch cubes.
When the meringue forms stiff peaks continue mixing on high and add the butter one cube at a time. Once all the butter has been added mix in all the vanilla and the spice mixture 1/2 teaspoon at a time until you have reached your desired flavor. You will not use all of the spice mixture, we used about 1-1/2 teaspoons. After the vanilla and spices have been added continue mixing on hight for 5 minutes to create your silky smooth buttercream.