Roast the squash: Preheat the oven to 400°F (200°C). Halve the spaghetti squash lengthwise, scoop out seeds, and brush cut sides with 1 tablespoon oil. Season with salt and pepper. Place cut-side down on a parchment-lined sheet and roast 35–45 minutes, until the flesh shreds easily with a fork.

Season the chicken: Pat chicken dry and cut into bite-size strips. Toss with Cajun seasoning, smoked paprika (if using), a pinch of salt, and black pepper.

Sauté the aromatics: Heat a large skillet over medium-high. Add remaining oil and 1 tablespoon butter. Sauté onion and bell pepper with a pinch of salt for 4–5 minutes, until softened and lightly browned. Stir in garlic for 30 seconds, until fragrant. Transfer veggies to a plate.

Cook the chicken: In the same skillet, add the remaining 1 tablespoon butter. Add the seasoned chicken in an even layer. Cook 5–7 minutes, turning as needed, until browned and cooked through. If the pan browns too fast, reduce heat slightly.

Build the sauce: Return the onions and peppers to the skillet. Pour in chicken broth, scraping up browned bits. Stir in heavy cream and bring to a gentle simmer for 2–3 minutes, until slightly thickened.

Add the squash: When the spaghetti squash is cool enough to handle, use a fork to shred it into strands. Add strands to the skillet. Toss to coat in the creamy Cajun sauce.

Finish and balance: Stir in Parmesan until melted and creamy. Squeeze in lemon juice to brighten. Taste and adjust salt, pepper, and Cajun seasoning. If you want more heat, add a pinch of cayenne.

Garnish and serve: Sprinkle with chopped parsley or green onions. Serve hot, with extra Parmesan and lemon wedges on the side.