Method
Preheat oven to 180°C and lightly grease a 33cm x 23cm baking dish.
Cook the spaghetti in a large pot of well-salted boiling water until just al dente (slightly firmer than you’d normally serve it, as it will continue cooking in the oven). Drain and set aside.
While the pasta cooks, melt the butter in a large, deep skillet or Dutch oven over medium heat. Add the onion and garlic, and cook for 2-3 minutes until fragrant.
Add the capsicum and cook for 5-6 minutes, stirring occasionally, until softened and starting to turn golden.
Add the mushrooms and cook for a further 2 minutes, just until they start to soften.
Pour in the cream, milk and chicken stock, and bring to a gentle simmer.
Add the cream cheese cubes, 1 cup of the white cheddar and the tasty cheese, stirring or whisking continuously until the sauce is smooth, thick and glossy, about 3-4 minutes.
Taste the sauce and adjust the seasoning with salt and pepper before adding anything else — this is the moment to get the flavour right.
Stir the shredded chicken and drained spaghetti through the sauce, tossing well until every strand is coated.
Transfer the mixture to the prepared baking dish, spreading it evenly. Scatter the remaining ½ cup of white cheddar over the top.
Cover with foil and bake for 20 minutes, then remove the foil and bake for a further 8-10 minutes, until golden and bubbling at the edges.
Rest for 5 minutes, scatter with fresh parsley, and serve.
Tips
Don’t overcook the spaghetti before baking – it should be properly al dente, as it will soften further in the oven.
Prep ahead to make this easier on a weeknight: chop the vegetables, shred the chicken and grate the cheese a day in advance, storing everything separately in the fridge.
For a slightly more grown-up flavour, swap some of the cheddar for grated Gruyère or fresh parmesan.
This dish reheats beautifully, making it a great option for leftovers or a meal-prep-friendly family dinner.
Serve with a simple green salad or steamed vegetables on the side to balance out the richness.
