This post will explain exactly how to slice a flank steak "on the bias", which is the best and ONLY way to cut a flank steak.
Flank Steak's Shape
Flank steak comes from the abdominal part of the cow. It's a relatively lean and flat piece of meat, with muscle fibers that mostly run in the same direction. Therefore, it's very easy to locate the grain, or "direction of the muscle fibers." Finding the grain is important! I'll get to that in just a moment.
A Misconception about Flank Steak
If I had a penny for every time I heard someone claim that flank steak is tough, I'd be a rich woman. The truth is, flank steak is very lean. Therefore, it has a slight chew to it. But if you know how to cook and cut a flank steak, you'll realize it's not actually tough at all.
How to Cut a Flank Steak "On the Bias"
Step 1: Sear the flank steak and let it rest for 4-5 minutes. For more on cooking flank steak, check out my recipe for Brunch Steak and Eggs.
Step 2: Locate the grain. As I mentioned, locating the grain is very straight-forward once you know what to look for. The grain looks like a bunch of lines all running in the same direction.
Step 3: Use a sharp chef's knife or carving knife to slice perpendicular to the grain, or "on the bias."
If you need a quick lesson in geometry, perpendicular means that when 2 lines meet, they form 90 degree angles. Think of the 2 lines as being the steak's grain and your knife.
Video Tutorial
I upload a lot of food-related instructional videos on TikTok. Check out this TikTok tutorial, Flank Steak with Calabrian Chili Butter, which includes a quick tutorial on how to cut a flank steak.
Why is it necessary to cut a flank steak on the bias?
Cows are strong animals with strong muscles. Cutting a flank steak on the bias allows you to make those long, strong muscle fibers shorter. Making them shorter means your teeth don't have to work as hard to break them down. It's that simple.
On the Bias, the namesake of this website, has other meanings too. If you're interested in learning more about the term, you can read about it here.