The Luther is a mysterious thing. It's an off-the-menu item at ChurchKey, which is the bar/casual/seat yourself establishment right above Birch & Barley. In my quest to try this elusive item, I came across two conditions one must know before frequenting Birch & Barley/ChurchKey. Such high barriers to entry to gain a taste of The Luther, which is $10.
1. Doughnuts are served at B&B only on Sundays, and you usually need a reservation. Luckily, brunch is served all day, well...11am-3:30pm, and then from 5-8pm.
2. You cannot make a reservation for ChurchKey, it's a seat yourself place, and you can only order The Luther during Sunday brunch hours. It is open all day for brunch, and it doesn't close between 3:30-5pm like B&B.
B&B doughnuts come in a trio: boozy butterscotch bacon, lemon poppyseed, and chocolate. Only the butterscotch bacon was worth it, I'd rate it a 4, but the rest were mediocre. The lemon poppyseed one wasn't overly lemony (a good thing, because I had one from Palena Market that was just lemony and oily, never to be had again), but I felt it was too faint of a flavor...since the flavor combination didn't evoke any memories of poppyseed muffins from Costco. Overall, with the faint flavors, the doughnuts didn't wow me enough to justify it's price. However, B&B made the doughnuts well; each was balanced in the yeasty doughiness and flavor.
The Luther sandwich. Served on brioche doughnuts, which were topped with glazed walnuts. Sandwiched inside is buttermilk fried chicken and two slices of applewood bacon. Actually, these brioche doughnuts were perfect, the best I've had thus far in DC, a solid 5, and I'd eat these over B&B's trio any day. The fried chicken was wonderfully delicious, crispy on the outside, you can taste the black pepper on the skin, and juicy and tender on the inside. If ChurchKey were able to combine LA's Honey's Kettle Fried Chicken with their brioche doughnut, that would be simply amazing. Honey's Kettle Fried Chicken uses a bit of honey in the batter to fry the chicken, which gives it a hint of honey sweetness, and personally, I would have preferred that to the peppery taste. I loved the fries as well, as I love skinny fries, crispy on the outside, and not all that potato-y...and these fit my criteria. After polishing off The Luther, I left most of the fries on the plate. All in all, The Luther is delightfully wonderful, and I'm happy to have tried it, because it is a unique DC brunch creation that all Washingtonians must try once in their life.