Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Place the chicken breast on a cutting board and gently pound it to an even thickness for uniform cooking.
In a shallow bowl, whisk the egg white. In another bowl, add the panko breadcrumbs seasoned with a pinch of salt and pepper.
Dip the chicken breast first into the egg white, then coat it evenly with the panko breadcrumbs.
Place the breaded chicken on the prepared baking sheet and bake for 20-25 minutes, or until the chicken is cooked through and the coating is golden and crispy.
While the chicken bakes, prepare the sweet and sour glaze. In a small saucepan over medium-low heat, combine pineapple juice, honey, rice vinegar, and soy sauce.
In a separate tiny bowl, mix the cornstarch with a small amount of water to create a slurry, then stir it into the saucepan.
Simmer the mixture for 3-5 minutes, stirring constantly, until the glaze thickens slightly.
Once the chicken is baked, drizzle the sweet and sour glaze evenly over the top, or serve it on the side for dipping.
Garnish with a sprinkle of freshly ground black pepper and serve immediately.