Mexican vanilla would make these sublime from BetterBaking.com - they are getting used to my creative vanilla recipes at this point!). This recipe makes tiny, not too sweet, pop-in-in-your mouth, mini muffins that are somewhere between a sweet muffin and a cake texture. If you also have ambrosial vanilla paste to swirl in, all the better. If not, scrapings from a vanilla bean (gourmet shops often carry them) will do. If you want to try this ASAP, you can use all-purpose flour; otherwise spring for the cake flour for yet an even more tender muffin.