Preheat the oven to 300°F.
Heat the olive oil in a large oven-safe skillet or braiser over medium-high heat.
Season the scored pork butt liberally with salt, pepper, chili flakes, dried oregano, and onion powder.
Sear the pork in the hot oil until browned on all sides.
Tuck the garlic cloves into the scored cuts of the pork.
Add the sliced onion, orange slices, fresh oregano, and thyme to the skillet.
Pour the mandarin squeezed juice around the edges of the skillet to deglaze.
Cover with a lid and transfer to the preheated oven. Braise for 2 ½–3 hours, or until the pork is fall-apart tender.
For the last 10 minutes, remove the lid and increase the heat to 450°F to brown and caramelize the fat cap.
Serve as tacos or over rice. Enjoy!