Put a rack in the middle of the oven and heat the oven to 350°F.
In a stand mixer or a large bowl, cream the butter and sugar.
Beat in the eggs, one at a time, until just mixed in.
Sift together the flour, baking powder, baking soda, salt, and nutmeg.
Combine the milk and Greek Yogurt
With a wooden spoon, mix a third of the dry ingredients into the butter mixture. Then mix in a third of the milk mixture. Continue mixing in the remaining dry and wet ingredients alternately.
Mix until well combined and smooth, but don’t overmix.
Grease and flour a standard-size muffin tin. Scoop enough batter into each tin so that the top of the batter is even with the rim of the cup, about ½ cup (use a #16 scoop if you have one). Reserve the remainder of the mix for the fritters, or make another 6 muffins.
Bake the muffins until firm to the touch, 25-30 min.
Melt the butter for the dipping mixture and combine the sugar and cinnamon. When the muffins are just cool enough to handle, remove them from the tin, dip them into or brush them all over with the melted butter, and then roll them in the cinnamon sugar.