Bayou Bakery, Coffee Bar & Eatery will begin its first day on Capitol Hill tomorrow with free coffee — in exchange for used mugs.

The second Louisiana-themed Bayou Bakery from chef David Guas will serve free Counter Culture Coffee drinks to the first 50 customers who donate a mug, beginning at 7 a.m. Tuesday. The eatery at 901 Pennsylvania Ave. SE then will use the cups to serve future customers.

Located in a former carriage house on the Hill Center grounds, Bayou Bakery eventually will offer Southern food and cocktails, in addition to coffee. The menu will include gumbo, beignets, mason jar cocktails and other favorites from the first Bayou Bakery, which opened in Arlington in 2010.

But Guas also is working on food unique to the D.C. location. The food includes a tea cake that Mary Todd Lincoln once made and a sandwich named after Benjamin Drummond, the first patient of the Civil War Naval Hospital, now the home of the Hill Center.

“I’ve always been a Civil War guy,” said Guas, as he sat in the feed room of the carriage house, which Abraham Lincoln commissioned in 1864. “I’ve always loved history.”

The restaurant, which holds 50 people inside and 40 people outside, will have a limited menu and hours this week. But it will eventually serve breakfast, lunch and dinner seven days a week.

The eatery normally will open at 6:30 a.m. on weekdays and 7:30 a.m. on weekends.

It will close at 10 p.m. every weekday, except Friday. On Fridays and Saturdays, the restaurant will close at 11 p.m. On Sundays, it will close at 8 p.m.