Preheat your oven to 350 and line your cupcake pan with cupcake liners.
In a bowl mix together cake flour, flour, sugar, and baking powder. Make sure these are combined well. With an electric mixer on medium speed, add butter. It will be easier to cut the butter into small squares at room temperature. Don't just add the whole stick.
In a separate bowl, whisk together eggs, milk, yogurt and vanilla extract. Add this to the dry vanilla cupcake ingredients and beat until combined but don't over beat!
With the vanilla cupcakes batter, fill lined cupcake tins until about 2/3 full. Bake for about 15-20 minutes (give or take a few). You will know your vanilla cupcakes are done when you pat on the tops and they spring back up at you. If they sink then the vanilla cupcakes need more time. If this is too confusing, you can always use the old toothpick in the center trick and that should do it.
As far as frosting the vanilla cupcakes goes, I would suggest using the buttercream frosting recipe. Decorate your vanilla cupcakes with colored sprinkles, sugar candies or fruit.