Boil the pasta: Bring a large pot of salted water to a boil. Cook pasta until just shy of al dente (about 1 minute less than package directions). Reserve 1 cup of pasta water, then drain.
Sauté aromatics: In a large skillet over medium heat, warm the oil.
Add onion and cook 3–4 minutes until softened. Stir in garlic and ginger for 30 seconds until fragrant.
Bloom the curry paste: Add Thai red curry paste to the pan. Cook 1–2 minutes, stirring, until it darkens slightly and smells toasty.
This step makes the flavor round and deep.
Build the sauce: Pour in coconut milk and broth, whisking to dissolve the paste. Add fish sauce (or soy), brown sugar, and a pinch of salt. Bring to a gentle simmer.
Add vegetables: Stir in bell pepper, snap peas, and zucchini.
Simmer 4–5 minutes until the vegetables are crisp-tender.
Add protein (if using): For shrimp, simmer 2–3 minutes until pink. For thin chicken slices, simmer 5–6 minutes until cooked through. For tofu or chickpeas, warm through for 3–4 minutes.
Toss with pasta: Add the drained pasta to the skillet.
Toss to coat, adding reserved pasta water a splash at a time until the sauce clings silkily to the noodles.
Finish with lime and herbs: Stir in lime zest and juice to taste. Season with salt and black pepper. Fold in chopped cilantro and Thai basil.
Serve: Top with extra herbs, chili flakes or sliced chili, and crushed peanuts if you like.
Taste and adjust lime, salt, and sweetness right before serving.