Bring a large pot of water to a vigorous boil. Salt it generously (about 1 tbsp sea salt for 4–5 L) — pasta water should taste like the sea. You salt early because it brings the water to the right seasoning temperature and prevents underseasoned pasta. Keep the pot simmering until you need it.

Make the steak rub: in a small bowl combine 2 tbsp olive oil, 2 minced garlic cloves, 2 tsp chopped rosemary (or thyme), 1 tsp sea salt and several grinds of black pepper. Rub this all over the trimmed 340 g (12 oz) skirt/flank steak and let it sit at room temperature for 15–20 minutes while you prepare other elements — this short rest allows the oil and aromatics to penetrate and the meat to come up slightly from refrigerator chill for even cooking.

Parboil/blanch the green beans: add the trimmed 200 g green beans to the boiling water and cook for 2–3 minutes until bright green and barely tender. Immediately transfer to an ice bath (or run under cold water) to stop cooking and preserve color. Blanching shortens the pan time and guarantees even tenderness while keeping a vibrant color and crunch. Reserve the pot of water for the pasta.

Cook the pasta: when the water returns to a boil, add the 150 g dry spaghetti and cook 1–2 minutes less than package directions (aim for al dente). Stir occasionally to prevent sticking. Reserve about 1 cup (240 ml) of hot pasta water before you drain — the starchy water will help marry the sauce and loosen the pan if it tightens.

While the pasta cooks, blister the tomatoes: heat a large skillet (preferably stainless steel or cast iron) over medium-high heat until hot. Add 1 tbsp olive oil (of the 2 tbsp for pasta) and the thinly sliced 2 garlic cloves; gently sizzle for 20–30 seconds until fragrant — don’t let garlic brown or it will turn bitter. Add the halved 240 g cherry tomatoes and a pinch of salt; let them sit without stirring for 2 minutes to blister and char slightly, then toss once and cook another 1–2 minutes until the skins begin to collapse. Blistering concentrates the tomato’s sweetness and develops smoky notes that deepen the sauce.

Sauté shallot and finish sauce: push tomatoes to one side of the pan, add the remaining 1 tbsp olive oil and the minced small shallot; sauté 1–2 minutes until softened and translucent (this sweetness balances the lemon). Add the reserved pasta water — start with ½ cup — and bring to a gentle simmer to loosen the pan and create a light sauce. Stir in 2 tbsp lemon juice and 2 tsp lemon zest to brighten; add the red pepper flakes if using for a hint of heat.

Toss the pasta: add the drained spaghetti directly to the tomato pan along with 4 tbsp grated Parmesan and most of the torn basil leaves (reserve a few for garnish). Toss vigorously (use tongs) for 1 minute, adding more reserved pasta water a few tablespoons at a time if needed to coat the spaghetti in a silky sauce. Tossing with starch and cheese creates an emulsion that lightly clings to the pasta — this is why you saved the pasta water.

Preheat your grill or heavy skillet to very high (cast iron or a hot grill pan works great). You want a surface that will give a fast, hot sear to develop a deep crust. Pat the steak very dry with paper towels (moisture creates steam and prevents browning) and season any exposed areas lightly with additional salt and pepper.

Char-grill the steak: place the steak on the hottest part of the grill or skillet. For a 12 oz skirt/flank steak approximately ¾–1 inch thick, sear 2½–3½ minutes per side for medium-rare (internal temp ~125–130°F / 52–54°C). If your steak is thinner, reduce the time. Don’t press the steak — letting it sit undisturbed develops a Maillard crust that holds flavor. If using a grill, rotate 90° halfway through each side to get crosshatch marks.

Rest and slice the steak: transfer the steak to a cutting board and let rest for 6–8 minutes. Resting lets the juices redistribute; cutting too soon will lose precious juices. Slice thinly across the grain (skirt or flank steak has long muscle fibers) — slicing against the grain shortens those fibers and gives a tender bite.

Finish green beans: while the steak rests, heat a dry skillet over high heat (or use the grill) and add the blanched green beans. Toss them over high heat for 2–3 minutes to blister and develop charred spots; season with a pinch of salt, a squeeze of lemon if you like, and a tiny drizzle of the steak oil if desired. Rapid high heat gives the beans a smoky, slightly crisp finish that contrasts the tender steak and pasta.

Plate and finish: twirl a portion of the lemon‑basil tomato spaghetti onto each plate, sprinkle with the remaining Parmesan and torn basil. Fan slices of the rested steak beside the pasta, spoon a few blistered tomatoes over the steak, and place a handful of blistered green beans along the side. Finish each plate with a light drizzle of good olive oil and an extra grind of black pepper. Serve immediately.