Put the paddle attachment onto the stand mixer. Add the butter and sugar to the mixing bowl.
Cream butter and sugar on high speed until light and fluffy.
Add eggs and egg yolks one at a time, beat thoroughly after each addition.
Blend flour, baking powder, salt and baking soda, in a bowl.
Cut open vanilla pod and scrape out seeds into the buttermilk. (You can dry the pod and use it to make vanilla sugar)
Add vanilla to buttermilk
Add ⅓ of the flour mixture to the butter mixture and beat on low until mixed.
Add ½ the buttermilk.
Continue to alternate the dry ingredients and buttermilk, ending with the flour.
Scoop cupcake batter into the lined cupcake pans. They should be about ¾ full.
Bake for 18-20 minutes.
Cool and frost with desired buttercream
Notes
You can replace 2 tablespoons of the buttermilk with vanilla brandy for a deeper flavor.Add French vanilla pudding mix (add it dry) to the flour mixture to give the cupcakes more flavor and make them moist.Storage:Store cupcakes in an airtight container at room temperature for up to 5 days.Freeze for up to 3 months.Tips:
Make your own vanilla sugar by burying two or three vanilla beans in a canister of sugar and leaving it for a week or so.
Use room temperature ingredients. Take butter, milk, and eggs from the fridge at least 30 minutes ahead of time.
Don't overmix the batter.
Line cupcake tins with cupcake liners and use a ¾ cup cookie scoop to fill them. This will keep them uniform in size and insure they bake evenly.