Prep your ingredients: Cut the chicken into bite-size pieces.
Slice the bell pepper and onion. Mince the garlic and ginger. If using lemongrass, smash it with the back of a knife to release the oils.
Warm the aromatics: Heat the oil in a large skillet or pot over medium heat.
Add onion, garlic, and ginger. Cook 2–3 minutes until fragrant and slightly softened, stirring often.
Bloom the curry paste: Stir in the red curry paste and cook for 30–60 seconds. This deepens the flavor and mellows any sharp edges in the paste.
Add coconut milk and broth: Pour in the coconut milk and chicken broth.
Stir until the curry paste is fully mixed in and the sauce looks smooth and red-orange.
Add chicken and flavor boosters: Add the chicken, kaffir lime leaves, and lemongrass if using. Bring to a gentle simmer. Cook 8–10 minutes, stirring occasionally, until the chicken is just cooked through.
Stir in pineapple and bell pepper: Add the pineapple and red bell pepper.
Simmer another 4–5 minutes. You want the pepper tender-crisp and the pineapple warmed but still juicy.
Season to balance: Add fish sauce, lime juice, and sugar if using. Taste and adjust.
You’re aiming for a balanced mix of salty, tangy, spicy, and sweet.
Finish and serve: Remove lemongrass and lime leaves. Sprinkle in chopped Thai basil or cilantro. Serve hot over jasmine rice.
Add extra lime at the table if you like it brighter.