In a medium bowl, whisk together the garlic, balsamic, Dijon, 2/3 of the olive oil, half the red pepper flakes, the rosemary, brown sugar, Worcestershire, 1 ½ teaspoons of Kosher salt (double this amount of Kosher salt if doubling the recipe), and freshly ground black pepper, to taste.

Place steak into a sealable plastic bag and pour marinade over the steak into the bag. Close bag and refrigerate. Marinate for at least 2 hours or up to overnight.

When ready to grill, remove steak from the refrigerator and let come to room temperature, 30 minutes to 1 hour.

Heat a grill over high heat to 400 degrees.

Prep the tomatoes. Make a tinfoil pouch. Add tomatoes, sugar, thyme, ½ teaspoon Kosher salt, freshly ground black pepper, remaining olive oil, and remaining red pepper flakes. Toss to combine and cinch the foil pouch closed.

Turn grill down to medium heat and oil your grates to prevent the steak from sticking. Place foil pouch of tomatoes onto the grill. Lift steak from the marinade, letting any extra juices fall off, and place onto the grill. Grill the steak for 10 minutes total, turning as needed and basting with extra marinade. Then grill another minute per side, continuing to baste, for medium-rare. (TIP: For best results, use a thermometer and grill until the internal temp is 130°F, as all grills are slightly different).

Remove steak from the grill and cover with foil, letting it rest for 5-7 minutes. If using grape tomatoes, they should be done; remove from the grill. If using cherry tomatoes, leave on the grill and close the grill, cooking for an additional 5 minutes while the steak rests, until softened.

Slice steak against the grain and serve with buttery tomato sauce.