This Grilled Flank steak is simply seasoned, grilled, then topped with caramelized onion sauce.
Ah, grilling season! I love you so. I especially love the chance to grill cuts like flank steak, that only taste good to me when cooked on the grill! This is our first flank steak of the season. Trust me, there are many more to come!
I love flank steak because it has intense flavor and is super affordable. We typically rub it in cumin and chili powder, grill it, and top it with fresh corn and tomato relish. YUM! But this time, I wanted to try something different. I spied this grilled flank steak recipe in my local grocery store's mailer, which typically has some pretty great recipes. They used rib-eye, which we have deemed a "sometimes food" due to the high price of beef right now. We decided to use flank steak instead of rib-eye.
Fair warning, this is not my normal weeknight recipe. The sauce, while very hands off, takes some time to simmer. I'd recommend planning this for a special weekend dinner!
Flank Steak vs. Skirt Steak
I chose flank steak for this recipe. You'll sometimes see flank steak and skirt steak compared, so it might be tempting to try this recipe with skirt steak!
Skirt steak is a long, fatty, very thin cut of meat that is best when marinated. This is often the meat that's used for fajitas. I often say that skirt steak has almost a "gamey" taste to it.
Flank steak is thicker and has less fat content.
If you do substitute skirt steak in this recipe, you'll need to reduce the cooking time per side by at least 2 minutes, depending on how thin the cut is.
Ready for flavorful grilled flank steak topped with a decadent sauce? Let's do it!
First, cut the onion into long slices. Add to a skillet with olive oil and butter, and set to cook and caramelize for about 25 minutes until golden brown.
While the onions are caramelizing, start the remainder of the sauce in a small saucepan. You'll add what feels like every condiment in your fridge (ketchup, soy sauce, lemon juice, etc.), but I promise it goes very quick and is worth it! Let the brown sauce simmer for about 25 minutes until it's well reduced and bubbly, then add to the finished caramelized onions.
While I was in the kitchen working on the sauce, my husband got the grill fired up. He rubbed the flank steak with garlic powder and black pepper, then threw it on a super hot grill for about 5 minutes each side. This yielded a steak that was medium rare through the middle, and medium on the thinner end pieces.
Since flank steak is lean, you do not want to cook it past medium. If you do, it will be tough.
How Long to Let Steak Rest
Once the steak is done, pull it off the grill and let it rest for 5-10 minutes before slicing it to let the juices re-distribute and lock into the meat. This is a tip that works for all steaks, regardless of how you cook them! If you slice immediately, the juice will run out of the meat.
How to Cut Flank Steak
After allowing the steak to rest for 5-10 minutes, cut the steak against the grain using a sharpened chef knife. It's important to cut flank steak into thin slices to keep it from being tough to chew.
For the steak
For the sauce
For the caramelized onion sauce
For the steak
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