Heat olive oil in a large deep sauté pan over medium heat. Add the onion with a pinch of salt and cook for 3–4 minutes until softened.
Add diced chicken, season with salt and pepper, and cook for 4–5 minutes until lightly golden.
Stir in garlic, courgette and red pepper. Cook for 2–3 minutes until just starting to soften.
Add the dry gluten-free pasta to the pan. Pour over the hot stock. Bring to a gentle boil, then reduce to a steady simmer. Cover and cook for 10–12 minutes (or according to packet instructions), stirring regularly to prevent sticking.
Once the pasta is tender and most of the liquid absorbed, stir in the lactose-free cream and lemon juice. Simmer uncovered for 2–3 minutes until lightly thickened.
Remove from the heat and stir through fresh parsley. Taste and adjust seasoning if needed.
Serve with extra parsley and Parmesan if using.