While prepping vegetables, combine the pineapple juice, rice vinegar, soy sauce, sesame oil, grated ginger, and sifted arrowroot powder in a small bowl, whisking until the arrowroot is fully dissolved and there are no lumps. This ensures the sauce will thicken smoothly later without clumping. Dice the red onion into bite-sized pieces, cut the red and yellow peppers into 1-inch chunks, and cut the broccoli into small, uniform florets so everything cooks evenly.

Heat the avocado oil in a large skillet or wok over medium-high heat until it shimmers. Add the chicken cubes and cook for 7-8 minutes, stirring occasionally, until the chicken is golden brown on the outside and cooked through (165°F internal temperature). I find this high-heat searing step develops a nice caramelized exterior that adds depth to the final dish. Transfer the chicken to a clean plate and set aside.

Return the same skillet to medium-high heat and add the diced red onion first, stirring for about 1-2 minutes until it becomes fragrant and slightly softened. Add the red pepper, yellow pepper, and broccoli florets, stirring frequently for 7-8 minutes until the vegetables are tender-crisp and the broccoli turns bright green. The vegetables should still have a slight bite to them, not be completely soft.

Return the cooked chicken to the skillet with the vegetables. Pour in the sauce mixture from Step 1 and gently fold in the pineapple chunks with their juice. Stir everything together over medium heat for 5-6 minutes, stirring occasionally, until the sauce thickens and becomes glossy. I like to let the mixture simmer gently rather than boiling hard—this keeps the chicken tender and prevents the arrowroot from becoming gummy. You'll know it's ready when the sauce coats the back of a spoon.

Divide the pineapple chicken and broccoli mixture among serving plates or bowls, spooning extra sauce over top. Sprinkle generously with sesame seeds for a nutty flavor and visual appeal. Serve immediately over steamed rice or your choice of grain.