Preheat your oven to 200°C (180°C fan) and line a large, rimmed baking sheet with baking parchment. This makes clean-up so much easier!

In a large bowl, toss the chopped bell peppers and red onion with the olive oil, salt, and pepper until evenly coated. Spread them in a single layer on the prepared baking sheet.

Roast the vegetables for 10-12 minutes, just until they begin to soften. What works best for me is giving them this head start so they don't end up undercooked when the chicken is ready.

While the vegetables are roasting, prepare the sauce. In a medium bowl or jug, whisk together the reserved pineapple juice, soy sauce, brown sugar, rice vinegar, minced garlic, grated ginger, and cornflour. Whisk until the cornflour is fully dissolved and there are no lumps.

In the same large bowl you used for the veg, add the chicken chunks and pineapple chunks. Pour over about two-thirds of the prepared sauce and toss well to coat everything.

Remove the baking sheet from the oven. Push the vegetables to one side and add the chicken and pineapple mixture to the pan, spreading it out into a single layer. Try not to overcrowd the pan for the best results, a key principle in all successful sheet pan cooking.

Return the sheet pan to the oven and bake for another 15-18 minutes, or until the chicken is cooked through and the vegetables are tender. A meat thermometer should read 74°C when inserted into the thickest part of the chicken, as recommended by the FSA.

For a final touch, brush the remaining sauce over the chicken and vegetables in the last 5 minutes of cooking. This creates a beautiful, thick glaze.

Once cooked, remove from the oven. Garnish with sliced spring onions and a sprinkle of sesame seeds before serving.