“Huh. They must be low on mustard” was my second thought after peeking under the hood of my salt beef sandwich from Duke’s Grocery ($9, 1513 17th St. NW). The first — if you’re curious — was, “How am I going to eat this whole thing?”

After taking a hefty bite, I realized why chef Alex McCoy (who co-owns the new cafe and pub with friend Daniel Kramer) used the condiment so sparingly: It. Is. SPICY.

Inspired by the East London sarnie of the same name, the salt beef sandwich at Duke’s is made with Colman’s Mustard, an incendiary spread made in the UK since 1814.

It adds a welcome zest to the fatty brisket, which McCoy brines for two weeks in cinnamon, spices and herbs before braising it for seven hours. The result is comparable to super-moist corned beef. It’s served on toasted rye bread from Lyon Bakery and comes with chunks of pickles made in-house.

In addition to other substantial sandwiches all under $10, Duke’s also serves shared plates (beef meatballs are made from McCoy’s great-grandmother’s recipe) and fancy cocktails, all of which you should have no problem finishing. I certainly didn’t.