Preheat oven to 350°F. Line a cupcake pan with paper liners.
In a medium bowl, add flour, baking powder, baking soda and salt. Stir together with whisk, and set aside.
In the bowl of an electric mixer, add eggs and beat 10-20 seconds. Add sugar and continue to beat on medium speed about 30 seconds. The mixture should be thick and fluffy. Add vanilla and oil, beat.
Reduce mixer speed to low and slowly add about half of the flour mixture. Add the milk, then the rest of the flour and the sour cream. Beat until just combined. Scrap down the side of the bowl.
The batter will be thin. Pour (or scoop) batter into a cupcake pan prepared with paper liners. Fill liners about 2/3 full.
Bake cupcakes in pre-heated oven for 12-14 minutes. Watch cupcakes carefully. The cupcakes are baked when the tops have a slight dome and the tops no longer appears moist in the center. The edges should be golden brown.