Flank Steak Peperonata

Peperonata is a mixture of sweet peppers, onion, tomato, and garlic, cooked in fruity olive oil until the peppers are soft and the flavors have melded. In order to get the flavors of both to marry, we cut the flank steak with the grain into three equal pieces, and seasoned all sides with salt, pepper, and oregano, and wrapped it in plastic for up to 24 hours to fully season the meat. Then we cooked red and yellow bell peppers, onion, and garlic in a hefty amount of extra-virgin olive oil until softened, added diced tomatoes, capers, red pepper flakes, and cooked the mixture until the vegetables were softened. After wiping out the skillet, we seared the seasoned steak pieces on all sides to a perfect medium-rare. While the meat rested, we stirred fresh basil into the peperonata mixture. To serve, we sliced the meat into smaller pieces, against the grain, seasoned the sliced with salt and pepper and the accumulated meat juices, and arranged the meat over the peperonata. A drizzle of extra-virgin oil balanced the tangy, meaty flavors. Look for a flank steak of even thickness. The peperonata can be made up to two days in advance.
 
2 pounds flank steak, trimmed
2 teaspoons dried oregano
1/3 cup plus 1 tablespoon extra-virgin olive oil, plus extra for serving
2 red bell peppers, stemmed, seeded, quartered, and cut crosswise into 1/4" strips
2 yellow bell peppers, stemmed, seeded, quartered, and cut crosswise into 1/4" strips
1 onion, quartered through root end and sliced crosswise into 1/4" strips
6 garlic cloves, crushed and peeled
14.5 ounce can diced tomatoes
2 tablespoons capers plus 4 teaspoons caper brine
1/8 teaspoon red pepper flakes 
1/2 cup chopped fresh basil

1. Cut steak lengthwise with grain into 3 equal pieces. Combine oregano and 2 teaspoons salt in bowl. Season steaks all over with salt mixture, wrap in plastic wrap, and refrigerate for at least 30 minutes or up to 24 hours.

2. Heat 1/3 cup oil in 12-inch nonstick skillet over medium-high heat until just smoking. Add red and yellow bell peppers, onion, garlic, and 1 1/4 teaspoons salt. Cover and cook, stirring occasionally, until vegetables are soft, about 10 minutes.

3. Stir in tomatoes and their juice, capers and brine, and pepper flakes. Continue to cook, uncovered, until slightly thickened, about 5 minutes. Season with salt and pepper to taste. Transfer peperonata to bowl, cover, and keep warm.

4. Wipe out skillet with paper towels. Pat steaks dry with paper towels and season with pepper. Heat remaining 1 tablespoon oil in now-empty skillet over medium-high heat until just smoking. Cook steaks until well browned and each registers 125 degrees (for medium-rare), 5 to 7 minutes per side. Transfer steaks to carving board, tent with aluminum foil, and let rest for 10 minutes.

5. Stir basil into peperonata. Slice steaks thin on bias against grain. Season steak slices with salt and pepper and drizzle with extra oil. Serve steak with peperonata.