Medium Rare in Cleveland Park has been an instant hit. The inspiration behind it is a Parisian restaurant that opened in 1959, Le Relais de Venice L’Entrecôte, where the menu couldn’t be simpler: It offers one fixed-price dinner—salad and steak frites—plus a handful of wines, and there are no reservations. Then, free of charge, you can get a second portion of steak and fries. Owners Tom Gregg and Mark Bucher, founder of BGR the Burger Joint, have made some American tweaks to much success.