First, I prepare the sweet and sour sauce by combining the pineapple juice, tomato puree, rice vinegar, brown sugar, and soy sauce in a bowl. I mix it well and set it aside for later.

Next, I coat the diced chicken breast fillets with 3 tablespoons of cornflour until they are evenly coated. This helps to make the chicken crispy when cooked. I then heat a large frying pan over medium-high heat and spray it with a little oil. Once the pan is hot, I add the chicken in batches, making sure not to overcrowd the pan. I let it cook for about 2-3 minutes without stirring to let it brown nicely on one side, then I turn it over to cook the other side until it’s fully cooked.

Once the chicken is browned and cooked through, I transfer it to a plate and set it aside.

In the same frying pan, I add the pineapple chunks first and let them cook for a few minutes until they caramelize. Then, I toss in the diced onion and peppers and stir-fry them for a couple of minutes until they start to soften.

Next, I pour the sweet and sour sauce over the vegetables in the pan. As the sauce begins to thicken, I add the cooked chicken back into the pan and toss everything together until it’s well combined and heated through.