Although the name of this place is Duke's Grocery, it is actually a tiny bar/restaurant near 17th & P Sts, NW that you could easily miss walking right past it. There's a very subtle sign out front that says "Duke's." The menu is exclusively appetizers and sandwiches.
We tried three sandwiches:
A chicken milanesa, salt beef, and their variation of a cubano. There is an emphasis on housemade, high quality ingredients, but the results are mixed.
The milanesa part of the sandwich was great, but the toppings of tomato, lettuce, and mashed avocado are icebox cold. Unappetizing on a hot sandwich. The salt beef (I wasn't sure what this would be) looks like corned beef. It is very tender, cut in thick slabs. As the name implies, less complicated in flavor than corned beef. The best was the cubano, with the pork served dripping moist. Very good, though I like the Fast Gourmet version better.
The star of their sandwiches are the housemade pickles. Extraordinary. This is not an expensive place, with the sandwiches topping out at $!2. Despite the low key exterior, the joint was jumping. So it looks like everyone found out about it before I did.
I would go back to investigate further, especially some of the appetizers like smoked trout or pork rillettes.