01 -
Mix together balsamic vinegar, olive oil, Dijon mustard, honey, garlic, salt, and pepper until well combined.
02 -
Place the flank steak in half of the prepared marinade and refrigerate overnight.
03 -
Remove the steak from the marinade, shaking off any excess, and grill over medium-high heat for 3-5 minutes per side or until the desired level of doneness is achieved. Let rest for 5 minutes.
04 -
Grill the cherry tomatoes until lightly charred, about 3-5 minutes. Alternatively, blister them in a heavy-bottom skillet over medium-high heat.
05 -
Slice the steak thinly against the grain, then top with blistered tomatoes, diced mozzarella, fresh basil, and the remaining marinade. Serve immediately.