Ingredients

1. One 1 3/4-pound flank steak
2. 4 garlic cloves, minced
3. 3 Thai bird chiles, minced
4. 1/4 cup extra-virgin olive oil
5. 3 1/2 cups chicken stock or low-sodium broth
6. 1 cup white polenta or stone-ground white cornmeal (5 1/2 ounces)
7. Salt and freshly ground pepper
8. 1/4 cup mascarpone
9. 1/4 cup freshly grated Parmesan cheese
10. Aged balsamic vinegar, for serving

Directions

1. In a large, shallow dish, coat the flank steak with the garlic and chiles. Drizzle with 2 tablespoons of the olive oil and set aside at room temperature for 2 hours.
2. In a medium saucepan, bring the chicken stock to a boil over high heat. Gradually whisk in the polenta and bring to a simmer. Cook over moderately low heat, whisking often, until the polenta is thick and no longer gritty, about 45 minutes.
3. Meanwhile, light a grill. Season the steak with salt and pepper and grill over a hot fire until nicely browned on the outside and medium-rare within, about 4 minutes per side. Transfer the steak to a carving board and let rest for 5 minutes.
4. When the polenta is tender, stir in the mascarpone, Parmesan and the remaining 2 tablespoons of olive oil. Season the polenta with salt and pepper.
5. Slice the flank steak against the grain 1/4 inch thick. Drizzle with balsamic vinegar and serve with the polenta.

Make Ahead

The flank steak can marinate overnight in the refrigerator. Bring to room temperature before grilling.