Tri Tip, originally called the California Cut, is a cut of beef from the bottom sirloin. It is called the tri tip because it literally has 3 tips, and looks like a triangle.
Unless you purchased your tri tip already trimmed up, it will come with a decently sized fat cap on one side and possibly some silver skin. You will want to remove both of these before marinating and grilling.
Add your marinade to the tri tip piece. Wrap it up in plastic and allow to marinate 8-24 hours.
This cut is traditionally cooked on a grill or smoked. But, we have found that tri tip cooks up beautifully in a braising liquid too.
It has rich beef flavor similar to a chuck roast. It also has beautiful marbling throughout which lends to the buttery flavor.
Combine the softened butter, mustard and black pepper in a bowl. Place in the middle of plastic wrap and roll it up, setting it in the fridge to combine and form a log.
As always, it is crucial to cut beef against the grain. Doing so ensures the most tender chew on any cut.