Preheat your oven to 200°C (180°C fan). Bring a large pot of well-salted water to a rolling boil. The water should taste as salty as the sea—this is your only chance to season the pasta from within. Drop in the pasta and cook for 2 minutes less than the packet instructions. You want it al dente with a distinct bite. When you drain it, the pasta will release a faint, starchy aroma. Set aside.

While the pasta boils, season the chicken thighs generously with salt and pepper on both sides. Heat the olive oil in a large frying pan over a medium-high flame until it shimmers and ripples. Lay the chicken in the pan in a single layer—you should hear an immediate, satisfying sizzle. Sear for 4-5 minutes per side until the skin is deeply golden and crisp. The smell at this stage is pure savoury comfort. Remove the chicken to a plate and let it rest for a few minutes before slicing into bite-sized chunks. The juices should run clear.

Reduce the heat to medium and add the diced onion to the same pan. Stir it around, scraping up any browned bits from the bottom—that's concentrated flavour you don't want to lose. Cook for 5-6 minutes until the onion turns translucent and softens, releasing a sweet, mellow fragrance. Add the minced garlic and stir for another 30 seconds until it becomes aromatic but not burnt.

Pour in the double cream and chicken stock, stirring constantly. Bring the mixture to a gentle simmer—you'll see small bubbles breaking the surface, and the colour will turn a pale, creamy gold. Let it bubble gently for 2-3 minutes, allowing it to thicken slightly. The sauce should coat the back of a spoon. Remove from the heat and stir in the pesto until fully incorporated. The colour will deepen to a vibrant green, and the basil scent will be unmistakable.

Return the cooked pasta to the pot (or tip it into a large mixing bowl). Pour the creamy pesto sauce over the pasta and toss well with tongs or a pasta fork. Every piece should be glistening and evenly coated. Fold in the sliced chicken, ensuring it's distributed throughout the mixture. The texture at this point should look glossy and inviting, not dry.

Transfer the entire mixture into a large baking dish (about 30cm x 20cm works well). Spread it into an even layer. Sprinkle the grated mozzarella evenly over the top, followed by the Parmesan. The cheese should form a blanket that peaks slightly in places. Bake in the preheated oven for 20-25 minutes, until the top is bubbling furiously and the cheese has turned a deep, golden brown with crispy edges. When you pull it out, the dish should be alive with sound and steam.

Let the bake rest for 5-10 minutes before serving. This is crucial—the sauce needs a moment to settle and thicken slightly. Garnish with fresh basil leaves if you have them, and serve straight from the dish. The first spoonful should reveal a creamy interior with perfectly tender pasta and juicy chicken.