Preheat oven to 350 degrees. Spray a bundt pan (the less ornate the better; I used an angel food cake bundt pan) with non-stick cooking spray and set aside.
In a small bowl, whisk together flour, baking powder, baking soda, salt, and nutmeg. Set aside.
In a large bowl, use a stand mixer or hand mixer to cream together butter and sugar very well.
Add sour cream and vanilla extract and mix well.
Beat in 1 egg at a time, mixing for 30 seconds or so in between each egg to produce a nice, fluffy batter.
Add 1/3 of the flour mixture to the batter, then 1/2 of the buttermilk. Continue rotating flour and buttermilk additions until all ingredients are combined. When adding the flour mixture and the buttermilk, only mix until the ingredients are just incorporated - do not over mix.
Transfer the batter to prepared bundt pan. Bake for 50-60 minutes or until a toothpick in the center of the cake comes out clean. Remove from oven and cool.
While the cake is cooling, prepare the glaze.