Cook the pasta. Bring a large pot of salted water to a boil. Cook pasta until just shy of al dente. Reserve about 1 cup of pasta water, then drain.

Mix the bang bang sauce. In a bowl, whisk 1/2 cup mayonnaise, 1/3 cup sweet chili sauce, 1–2 tablespoons Sriracha (to taste), 1 teaspoon honey, and 1–2 teaspoons rice vinegar or a squeeze of lime. Add a pinch of salt. Taste and adjust the heat and sweetness. Set aside.

Season the shrimp. Pat shrimp dry. Toss with salt, black pepper, and a pinch of red pepper flakes if you like it spicy. Dry shrimp sear better and stay juicy.

Sear the shrimp. Heat 1 tablespoon oil and 1 tablespoon butter in a large skillet over medium-high heat. Add shrimp in a single layer. Cook 1–2 minutes per side until pink and opaque. Transfer to a plate. Do not overcook.

Sauté the aromatics. Lower heat to medium. Add a drizzle more oil if needed. Add minced garlic (2–3 cloves) and the white/light green parts of sliced scallions. Cook 30–45 seconds until fragrant, not browned.

Build the sauce in the pan. Reduce heat to low. Add the bang bang sauce and 1/4–1/3 cup reserved pasta water. Stir until smooth and slightly warmed. You want a silky, pourable sauce. Add more pasta water if it’s too thick.

Toss the pasta. Add the drained pasta to the skillet. Toss to coat evenly. Add the shrimp back in with any juices. Warm through for 1–2 minutes. Finish with lime zest and a squeeze of lime juice for brightness.

Garnish and serve. Top with the dark green parts of the scallions. Sprinkle sesame seeds or chopped cilantro if you like. Taste and adjust salt, heat, and acidity before serving.