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Bring the Italian steakhouse vibe right to your home with this juicy Grilled Flank Steak Caprese. The secret's in the tangy balsamic marinade that softens the meat while packing it with deep, bold flavors. When you mix those slightly charred tomatoes with soft bocconcini cheese, you're basically combining everyone's favorite Caprese salad with a perfectly grilled steak. It's the kind of fancy-looking meal that's actually super easy to pull off.
When I made this for a family get-together last summer, my tomato-hating nephew couldn't stop himself from trying those grilled cherry tomatoes. Everyone was shocked when he not only ate them but asked for more. Now he bugs me to make this whenever he comes over.
Key Ingredients and Smart Shopping Advice
- Flank Steak: Pick one with even thickness and some fat running through it. The meat should look bright red with a bit of marbling - this helps make it taste better and stay tender
- Balsamic Vinegar: Go for a middle-of-the-road balsamic. You don't need to spend big bucks on the aged stuff, but the super cheap bottles can taste too sharp
- Olive Oil: Use standard olive oil in your marinade and save the fancy extra virgin stuff for drizzling at the end
- Grainy Mustard: Brings a nice pop of texture and tang - you can use Dijon if that's all you've got, but whole grain looks better and adds more texture
- Fresh Garlic: Look for bulbs that feel heavy and have tight cloves. The jarred minced stuff just won't give you that same flavor kick
- Cherry Tomatoes: They should be deep red and feel firm when you touch them. Using mixed colors can make your plate look even prettier
- Bocconcini: Try to find pearl or cherry-sized balls in water. They should be bright white and firm to touch
Step-by-Step Cooking Guide
- Step 1: Making Your Marinade (15 minutes)
- Mix 1/2 cup balsamic vinegar with 1/3 cup olive oil until they're well combined. Stir in 3 tablespoons grainy mustard and 2 tablespoons honey until everything's smooth. Chop up 4 big garlic cloves finely and add them in. Throw in 1 teaspoon black pepper and 1 1/2 teaspoons salt. Put your steak in a wide, shallow container and pour the marinade all over it, making sure both sides get coated. Cover it up tightly and stick it in the fridge for at least 4 hours, though 8 hours works even better.
- Step 2: Getting Ready to Grill (10 minutes)
- Take your steak out of the fridge about 30 minutes before cooking. Make sure your grill grates are super clean and rub them with oil. Get your grill nice and hot to medium-high (around 400-450°F). Put some olive oil in a small bowl with a brush for your tomatoes. Have a plate ready for your cooked steak.
- Step 3: Cooking the Steak (12-15 minutes)
- Take the steak out of the marinade but save the liquid. Pat the steak dry with paper towels so it doesn't steam. Put it on the hottest part of your grill. Let it cook for 5-6 minutes on the first side without touching it. Flip it just once and cook another 4-5 minutes for medium-rare. Check with a meat thermometer (130°F is perfect for medium-rare). Move it to your plate and loosely cover with foil.
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My family's always been picky about flank steak. It was my grandma's go-to for Sunday meals. She always told me that while the marinade matters, letting the meat rest properly is what really counts. When I follow what she taught me, the steak comes out tender every time.
Perfect Temperature Recommendations
I've found that 130-135°F gives you that gorgeous pink middle while keeping everything nice and tender. A bunch of my blog followers who used to think medium-rare was too pink have completely changed their minds after trying steak cooked to this temperature.
Prep-Ahead Strategies
- You can mix up the marinade up to 3 days before and keep it in the fridge
- Get the tomatoes ready ahead and just leave them out at room temp until you're ready to grill
- Any steak you don't finish tastes great cold or at room temperature the next day
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After tweaking this dish for years, I can honestly say it's become one of my most reliable home runs. There's something about mixing that juicy, full-flavored meat with popped tomatoes and smooth bocconcini that hits all the right notes - it feels fancy but tastes like comfort food too.
Keeping and Warming Leftovers
If you somehow end up with extras, put them in a sealed container in the fridge for up to 3 days. The steak actually tastes best when you let it come to room temperature, but you can also warm it gently in foil in a cool oven. I wouldn't save the tomatoes and cheese though - they really taste best fresh, so only grill what you plan to eat right away.
Frequently Asked Questions
- → How long do I marinate the steak?
- Leave it in the marinade for 4 to 12 hours. Longer than 12 hours can make it mushy.
- → What if I don't have a grill?
- A grill pan or your oven's broiler works just as well.
- → What's a good bocconcini swap?
- Mini mozzarella balls or mozzarella slices both work great.
- → How do I check if my steak's ready?
- Use a meat thermometer: 135°F gives you medium-rare, 145°F for medium.
- → Why cook the marinade down?
- Heating makes it safe to eat and turns it into a tasty sauce for the steak.