Combine the sour cream and baking soda; set aside.
Cream the butter and sugar together, then beat in the egg and vanilla.
Whisk the flour and nutmeg together, then add to the bowl, alternating with the sour cream mixture until they are both combined.
Roll in wax paper and refrigerate for an hour. If you are using cut-outs, cover in the bowl and refrigerate for an hour.
Remove from the fridge and slice into round circles about 1/2 inch thick ( these are NOT thin cookies!) or alternately, roll out the dough until it's 1/2 inch thick and cut out the cookies.
Pre-heat your oven to 350 degrees.
Bake in the oven for 10-12 minutes, until the bottom has browned slightly. Depending on your oven, this could take up to 15 minutes. Just watch the bottoms!
Remove and cool cookies completely.
Prepare a batch of my Buttercream Frosting.
Frost the cookies and decorate with sprinkles of your choice!
Keep in a sealed container for up to 4 days - these also freeze very well!