I hope you've heard of Philadelphia Butter Cake. If you haven't, pop over to this here link to learn a bit more about it. Don't worry, I'll wait.
But wait, there's more. In Northeast Philadelphia, as I heard, there was a bit of a battle over whose Butter Cake was superior: Haegle's or Mayfair Bakery, two bake shops a mere few blocks from one another.
Well, I didn't need much more urging than that to see for myself. So I went to both Haegle's and Mayfair Bakery, and sampled both. Along with some friends, I had a tasting.
First, the bakery experience. Here is what Haegle's looks like. 
and inside, here's what the Butter Cake looks like:
...also, for what it's worth, they had these things that I'd never seen before: 
The bakery employee was very friendly, answering all my questions with a smile. How long have you been here? Since 1930, though not me personally. What's a wien cake? A vaguely Lamington-esque cake, topped with vanilla or chocolate frosting.
And then, on to Mayfair Bakery. Inside of Mayfair Bakery, the cake looks like this:
...and they also had these:
And after you exit the premises with your cake, this is what you'll be looking at: 
At both bakeries, the butter cake was sold not by the slice but by the slab. Sort of like a quarter-sheet of it. I found it interesting that it was only sold this way or as a larger sheet size--no single servings. A quarter-sheet was $5.75 at Haegle's and $5.85 at Mayfair, I believe--they were very close in price.
Here they are, together.
Care for a closer look? OK. Here's the cake from Haegle's, a little more crackly on top: 
Here's the cake from Mayfair Bakery: a little more crater-y looking: 
Here's the slice from Haegle's. Haegle's had a little more ooze and a more dense crust base:
and here's the one from Mayfair. Definitely a more puffy yeast base, more like a light bread. Overall, easier to eat from your hand without getting all messy.
and finally, it was time to taste.
We judged them on a few criteria: texture, presentation, taste, and overall.
In terms of TEXTURE, the Haegle's cake was definitely more gooey, which was pleasant against the dense yeast crust. The Mayfair version ran a little drier, which was nice for eating in-hand, but was not as satisfyingly decadent. Texture winner: Haegle's.
In terms of PRESENTATION, both cakes were on an even par. Our tasters were split between which aesthetic--crackly or cratery--was preferred, but ultimately, Mayfair took the cake because the cake was in its own little aluminum pan, which made transport easier. Presentation winner: Mayfair.
In terms of TASTE, it was a tough split, but ultimately, the more gooey Haegle's won the vote. The drier Mayfair variety is a fantastic morning cake, but Haegle's variety, tasters felt, was such that it could be eaten all day. The crust, more dense, also had a more rich flavor. Taste winner: Haegle's.
OVERALL? Well, both were fantastic Butter Cake experiences, and I'd highly recommend both. If you asked me to bring a butter cake from just one or the other, I'd probably go to Haegle's first. But the cakes are both of such fine caliber that if the first stop had run out, I'd be equally proud to come toting a bakery box from the other.
Haegle's Bakery: 4164 Barnett Street, Philadelphia, PA 19135 (map) (215) 624-0117
Mayfair Bakery: 6447 Frankford Avenue, Philadelphia, PA 19135 (map); (215) 624-7878;mayfairbakery.com
Read more about butter cakes I've eaten on Serious Eats!