It should no longer come as a surprise to see burgers constructed with non-bread food items for buns. In fact, there have been several notable buns throughout American history: mac n’ cheese buns, scallop buns, deep-fried Twinkie buns, fried peanut-butter-and-jelly sandwich buns, pizza buns—and, of course, the much-coveted ramen burger with noodle buns.

Now that the “innovative” burger bun craze is in full-swing, L.A.-based Fatburger—where “size does matter”—has allegedly debuted a “protein-style burger” that uses two lean hamburger patties as buns. Other good things stuffed between the patties: lettuce, pickles, relish, onions, and mustard. This new Fatburger creation is perfect for all those Paleo nuts out there addicted to CrossFit.

The burger will be available starting today at the Beverly Hills Fatburger location, at $4.50 for a small.

It should be noted that In-N-Out has been serving a “protein-style” burger (which can be found on the chain’s secret menu) for quite some time now. Instead of burger patties as buns, the In-N-Out protein burger is served wrapped in iceberg lettuce.

[via Eater]