Preheat the oven to 350 degrees F and spray two ramekins with cooking spray. In a medium sized bowl, cream together the butter and sugar until light and fluffy.
Beat in the egg and vanilla extract. In a separate bowl, mix together your dry ingredients. Add the flour mixture to the butter mixture and stir until well combined.
Stir in the milk until the batter is smooth. Divide evenly between the two ramekins. Bake in the preheated oven for about 20-25 minutesor until a toothpick inserted in the center of the cake comes out mostly clean with moist crumbs attached.
Remove from the oven, set on a cooling rack and allow them to cool for a few minutes. You can drizzle chocolate ganache or frosting over the top and enjoy.