– Sour Cream – makes the cupcakes moist and tender. – Pure Vanilla Extract – you can’t call them vanilla cupcakes without using real vanilla! Try making your own homemade vanilla extract (it’s great as gifts too!). – Butter Extract – this isn’t as hard to find as you’d think, it’s pretty readily available in the baking or spice section of your grocery store. Butter extract gives these cupcakes a hint of butter flavor without using butter in the batter.