This is a full case of USDA Prime beef bottom round flat, sold by the pound, available at Costco warehouse locations. The bottom round flat is the largest section of the bottom round, a lean and flavorful boneless cut from the round primal in the hind quarter of the animal. It is composed primarily of the biceps femoris muscle — a hard-working muscle that produces lean, firm-textured beef with excellent, robust beefy flavor.

USDA Prime is the highest quality grade awarded by the USDA, reserved for beef with the most abundant marbling. The superior marbling found in Prime-grade beef translates to richer flavor, more moisture, and greater tenderness compared to Choice or Select grades. Purchasing as a full case offers exceptional value for restaurants, caterers, butcher shops, or households preparing large quantities.

The bottom round flat performs best with low-and-slow cooking methods, including oven roasting at 150–170°F, braising, and slow-cooker preparation. It is also ideal for thin slicing across the grain for deli-style roast beef, London broil, carne asada, and beef jerky. Marinating before cooking further enhances tenderness. This cut is also known as the Outside Round or Bottom Round Oven Roast.