Measure and prep everything first (mise en place): slice the red bell pepper thinly, shred or rinse the cabbage if needed, slice green onions, chop parsley, mince garlic, and pat the shrimp and scallops very dry with paper towels. Why: having everything ready keeps the quick stir‑fry moving and patting the seafood dry ensures a fast, clean sear instead of steaming.

Soak the rice noodles: place the dried rice noodles in a large bowl and pour enough lukewarm water to cover. Let sit 8–12 minutes until pliable but still slightly firm (they’ll finish cooking in the pan). Why: rice noodles easily overcook and turn mushy; pre‑softening them gives even texture while the hot pan finishes them quickly without breaking.

Season the seafood: in a shallow bowl, toss the shrimp and scallops with 3 tsp of the Cajun seasoning, a pinch of salt and a couple grinds of black pepper. Let rest 5 minutes. Why: the short rest lets the seasoning adhere and begins flavor infusion without curing the seafood — you want spice on the surface for browning.

Heat a large heavy skillet or wok over medium‑high heat until hot. Add 2 tbsp of the olive oil and swirl to coat. Add the shrimp in a single layer and cook undisturbed 1–1½ minutes per side until just opaque and nicely seared; remove to a plate. Why: high heat and minimal movement produce a golden sear that locks in juices and gives texture; removing shrimp prevents overcooking while you cook the scallops.

Add the remaining 1 tbsp oil to the same pan and drop in the scallops in a single layer. Sear 1–2 minutes per side until the exterior is golden and the center is translucent; remove with the shrimp. Why: scallops cook very quickly and are best when they develop a caramelized crust for flavor while remaining tender inside.

Lower heat to medium and add the remaining 1 tbsp oil. Sauté the minced garlic for 20–30 seconds until fragrant (do not brown), then add the sliced red bell pepper and shredded cabbage. Stir‑fry 2–3 minutes until vegetables begin to soften but remain crisp. Why: cooking the aromatics briefly releases flavor; quick high‑heat cooking preserves the bright color and crunch of the vegetables.

Drain the soaked rice noodles and add them to the pan along with the green onions, remaining 1 tsp Cajun seasoning, and the lemon juice. Toss gently with tongs to combine and let the noodles warm through 1–2 minutes. Why: adding noodles now allows them to pick up pan flavors and absorb the lemon and spice; tossing (not stirring wildly) prevents them from tearing.

Return the seared shrimp and scallops to the pan, tossing everything together just until the seafood is heated through (about 30–60 seconds). Taste and adjust seasoning with salt, pepper, and additional lemon if desired. Why: finishing in the pan melds flavors while avoiding overcooking the delicate seafood.

Finish and garnish: remove from heat and stir in the chopped parsley and a drizzle (optional) of extra virgin olive oil or a small pat of butter for gloss. Serve immediately with extra lemon wedges. Why: fresh herbs brighten seafood and a final fat adds silk and sheen to the sauce, rounding flavors the way restaurants do.

Plating suggestion: divide noodles between warm shallow bowls, arrange seafood on top, scatter extra green onions and parsley, and finish with another twist of black pepper. Why: warm bowls help keep the dish hot and showcasing the seared seafood on top highlights the textures you worked to create.