Preheat oven to 350 degrees.
Line an 8x8 or 9x9 inch baking dish with foil and grease with non stick spray.
In a large bowl combine the butter, sugar, milk, and vanilla.
Add egg, and stir to combine.
In a separate bowl combine the cream of tartar, baking soda, salt, cinnamon, nutmeg, and flour.
Whisk dry ingredients for 1-2 minutes.
Stir dry ingredients into butter mixture until combined.
Pour batter into prepared pan.
In a small bowl combine the cinnamon and sugar for topping, and sprinkle over the batter.
Bake 20-25 minutes.