Add butter to Le Creuset Dutch oven and melt on medium heat.
Slice onion. Add to Dutch oven.
Continuously stir until lightly browned on medium heat.
Meat mallet chicken to consistent 1" or 2.5 cm thickness. Add garlic powder, salt, pepper, and smoked paprika to both sides.
Push onion to side and add chicken breast. Leave for 6 minutes until lightly browned. Flip, add onion on top, and cook another 5 minutes.
Add diced red and yellow peppers. Cook for another 2 minutes.
Add pineapple and cover. Stirring occasionally.