Flank Steak Tacos

For the herb paste: pulse cilantro, garlic, scallions, jalapeno, and cumin in food processor until finely chopped, ten to twelv 1-second pulses, scraping down sides as necessary. Add oil and process until mixture is smooth and resembles pesto, about 15 seconds, scraping down sides of workbowl as necessary. Transfer 2 tablespoons herb paste to medium bowl; whisk in lime juice and set aside.

For the steak: Using a dinner fork, poke each piece of steak 10 to 12 times on each side. Place in a large baking dish; rub all sides of steak pieces evenly with salt and then coat with remaining herb paste. Cover wiht plastic wrap and refrigerate at least 30 minutes or up to 1 hour.

Scrape herb paste off steak and sprinkle all sides of pieces evenly with sugar and pepper. Heat oil in a 12-inch heavy-bottomed nonstick skillet over medium-high heat until smoking. Place steak in skillet and cook until well browned, about 3 minutes. Flip steak and sear until second side is well browned, 2 to 3 minutes. Using tongs, stand each piece on a cut side and cook, turning as necessary until all cut sides are well browned and the internal temperature registers 125 to 130 degrees on an instant-read thermometer, 2 to 7 minutes. Transfer steak to cutting board and let rest for 5 minutes.

For the tacos: Using a sharp chef's knife or carving knife, slice steak pieces across grain into 1/8-inch thick slices. Transfer sliced steak to the bowl with the herb past-lime juice mixture and toss to coat. Season with salt. Spoon a small amount of sliced steak into the center of each warm tortilla and serve immediately, passing toppings separately.