01 -
Season chicken breasts evenly with red pepper flakes, garlic salt, onion powder, paprika, and black pepper.
02 -
Heat a large skillet over medium-high heat. Sear chicken for 3 minutes per side until lightly golden.
03 -
Transfer seared chicken to the bottom of the slow cooker.
04 -
Scatter chopped red bell pepper, red onion, and pineapple chunks over the chicken.
05 -
In a small bowl, whisk together 1 cup reserved pineapple juice, brown sugar, soy sauce, honey, apple cider vinegar, and cornstarch until thoroughly combined.
06 -
Pour sauce mixture evenly over chicken and vegetables.
07 -
Cover and cook on low for 6 hours or on high for 4 hours until chicken is fully cooked and tender.
08 -
Garnish with sliced scallions if desired. Serve warm.