Preheat a large pot over medium heat. When the pan is hot but not smoking, add the oil and butter, swirl to coat the bottom of the pan.
Add the chicken, salt and pepper and garlic seasoning. Brown the chicken until it's cooked and slightly seared, don't overcook.
Remove the cooked chicken from the pan, leaving the juices in the pan for added flavor.
Add a couple big dollops of the curry paste and stir fry for a minute to release the flavors. Then add the diced onion and minced garlic. Cook stirring occasionally until just tender, 3-4 minutes.
Next add the coconut milk, diced bell pepper, and lime leaves to the pan. Stir to combine while bringing the curry to boil.
Then lower the heat to maintain a bare simmer. Cook until the bell pepper is tender, 6-8 minutes.
When the bell pepper is tender, add the chicken and mushrooms to the curry and stir to combine. Then add the pineapple and stir to combine again.
Bring the curry back to a simmer and cook until everythingfeels done, but not mushy. Remove the curry from the heat and season to taste with the coconut sugar, fish sauce, and sea salt if desired.
Remove the lime leaves and serve with freshly steamed rice.
