Add onion, fresh pineapple chunks, soy sauce, rice wine vinegar, honey, sesame oil, garlic, five-spice powder, bell pepper, jalapeño pepper, and peanut butter to a 5 or 6-quart (4.5-5.5L) slow cooker pot. Stir to combine thoroughly.

Heat olive oil in a large skillet over medium-high heat. Season trimmed pork roast on all sides with salt and pepper, to taste. Add to hot skillet and sear on all sides, approximately 2-3 minutes per side. Transfer seared pork to slow cooker pot.

Reduce heat to medium and deglaze skillet with fresh pineapple juice. Use a spatula to scrape up flavorful brown bits from the bottom of the pan. Remove from heat and pour pan juices into the slow cooker.

Cover and cook over high heat for 3-4 hours or low for 6-8. When finished, stir in fresh cilantro and transfer pork and pineapple mixture to a serving platter with a slotted spoon. Cover and keep warm.

Optional: If desired, create a slurry by combining 2 tablespoons arrowroot and ¼ cup of juices from the slow cooker. Transfer remaining juices from the slow cooker to a large skillet over medium-high heat and whisk in the arrowroot slurry until well combined. Cook for several minutes or until sauce is reduced and thickened.

To serve, spoon warm pork and pineapple mixture over a bed of cooked brown, white or cilantro-lime rice. Top with the juices or thickened sauce, if desired, and enjoy!