The dish: Royal of mussels, offered regularly as a special

Where to get it: Et Voila!; 5120 MacArthur Blvd. NW; (202) 237-2300; etvoiladc.com

Price: $14.50

What it is: Oblong spheres of mussel custard nestled among mini choux puffs and mussel salad, all swimming in a tomato gazpacho and finished with micro cilantro and basil oil. The custard is made using a French technique that involves heating a blend of eggs and cream to 185°F so it thickens but doesn’t scramble. The liquid released when mussels are cooked is added to the mixture to impart briny umami undertones. The custard is then chilled and set in molds.

What it tastes like: Chef Claudio Pirollo describes the appetizer as “everything in one dish” because of the broad contrasts in flavor and texture. The rich, velvety mussel custard is balanced by the bright acidity of gazpacho and the light crunch of choux pastry and crisp micro cilantro. Saffron, Espelette pepper, and lemon season the mussel-infused custard, and the lightly cooked and dressed mussels serve as a visual reminder of the star ingredient.

The story: European menus are often graced by a royal of asparagus or royal of tomato—a savory custard with juice or purée from a flavorful ingredient. One of Pirollo’s former chefs back in Belgium once prepared a royal of mussels, made with mussel juice and a tiny variety of shrimp from the North Sea. A surplus of mussel juice in the fridge at Et Voila! inspired Pirollo to try the royal method with the restaurant’s signature mollusk. He reduces the mussel juice by half to intensify the taste before adding it to the custard.