Prepare the marinade and beef: In a bowl, whisk together 3 tbsp low-sodium soy sauce, 2 tsp brown sugar (or honey), 2 tsp gochujang, 2 tsp sesame oil, 2 minced garlic cloves, and 1 tsp grated ginger. This mixture balances salt, sweet, heat and toasted sesame aroma; whisking dissolves the sugar and emulsifies the oil so the flavors coat the meat evenly. Add the 320 g thinly sliced beef and toss to coat. Let sit at room temperature for 10 minutes (or up to 30 minutes in the fridge) so the thin slices absorb flavor without the texture breaking down from over-marinating.

Toast the sesame seeds and dry-toast the spaghetti: Heat a small dry skillet over medium heat. Add 2 tsp sesame seeds and toast, shaking the pan, until fragrant and lightly browned, 1–2 minutes; this releases the sesame’s oils and gives a deeper nutty flavor. Remove seeds to a small bowl. In the same skillet (cleaned and dry), break the 150 g whole-wheat spaghetti in half if needed and toast over medium heat for 2–3 minutes, turning frequently until it smells toasty and slightly darker — toasting the pasta adds an extra layer of nutty complexity that elevates ordinary spaghetti.

Cook the spaghetti: Bring a large pot of salted water to a rolling boil (about 1 tsp salt per liter). Add the toasted spaghetti and cook to al dente according to package directions, usually 7–9 minutes for whole-wheat. Reserve ½ cup (120 ml) pasta cooking water just before draining — the starchy water helps bind the sauce and loosen the spaghetti while keeping the dish silky. Drain the pasta and set aside.

Blister the sugar snap peas and warm the carrots: Heat a large heavy skillet or cast-iron pan over high heat until shimmering. Add 1 tbsp neutral oil and the 160 g sugar snap peas in a single layer (give the pan a moment to get hot first). Let them sit without stirring for 45–60 seconds to develop a blistered char, then toss for another 30–45 seconds until bright green and tender-crisp. Remove to a bowl and quickly add the remaining 1 tbsp neutral oil and the 60 g julienned carrot; sauté 30–45 seconds just to warm and slightly soften the carrots so they keep a little crunch but are no longer raw tasting.

Sear the beef for maximum flavor: With the pan still very hot, add the marinated beef in a single layer (work in two quick batches if the pan is crowded). Spread the slices so they make contact with the pan — high heat creates immediate caramelization (the Maillard reaction) that gives bulgogi its signature savory-sweet crust. Sear without moving for 30–60 seconds per side for thin slices, tossing once or twice, until edges are browned and the beef is just cooked through; thin beef cooks very quickly — overcooking makes it tough.

Bring the dish together: Reduce heat to medium. Return the blanched peas and carrots to the pan with the beef; add the drained spaghetti and 2 tsp of the reserved pasta water to loosen. Toss to combine, adding more pasta water 1 tbsp at a time if needed until the sauce lightly coats the pasta and meat. The small amount of pasta water and soy/gochujang marinade create a glossy, clingy sauce that adheres to both noodles and beef.

Finish and season: Remove from heat and stir in the toasted sesame seeds and 2 tbsp sliced green onion. Taste and adjust with salt and freshly ground black pepper if needed (the soy sauce provides salt, so taste before adding more). Squeeze a lime wedge over each serving for an acidic lift that brightens the savory-sweet flavors and cuts through the sesame oil richness.

Plate and garnish: Twirl the sesame spaghetti onto warm plates, top with the bulgogi beef and blistered sugar snap peas, scatter any pan juices over the top, sprinkle with additional toasted sesame seeds and green onion, and serve with a lime wedge on the side. Serve immediately so the noodles remain silky and the beef is warm and tender.