WASHINGTON — There’s no longer a need to separate the bun from the burger.

On Dec. 19, Shake Shack introduced gluten-free burger buns at all seven of its D.C.-area locations. The new menu item costs an additional $1.

Other popular burger restaurants, including Five Guys, Elevation Burger and Burger Tap and Shake, have the option for customers avoiding gluten to wrap their burgers in lettuce or to opt out of a bun, altogether. However, gluten-free buns are not offered.

Penn Quarter’s b. restaurant says it can prepare most of its burgers without gluten, and the concept charges $0.99 for a gluten-free roll.

Along with gluten-free burger buns, Shake Shack added half-bottles of prosecco to its beer and wine menu. The bubbly costs $15.