I don't know what this stuff is, but if you've got a Costco near you, you owe yourself a taste of this steak.
They label it "Beef Loin, Top Sirloin, Boneless Cap Off Prime."
It's an inch and a half thick, and $8.99 a pound, and it's spectacular. More tender than the best Filet Mignon and with a gorgeous steak flavor.
We had it with tiny Yukon Gold tater chunks, pan-fried in onions and garlic.
The steak was rubbed with pepper and salt, and grilled to perfection.
The best bite of beef I've had in a long long time.