Place the cooking fat in the bottom of the Instant Pot and turn on the saute function. When the fat has melted and the pot is hot, add the onion, and cook, stirring, until translucent, about 5 minutes. Add the garlic and cook for 30 seconds, until fragrant. Turn off the heat.
Add the pineapple, salt, spices, and shoulder roast pieces and stir to coat the meat with the mixture. Close and lock the lid and set to manual - high pressure for 75 minutes.
When the timer goes off, turn the warming function off and allow to depressurize naturally. This step is essential for tender carnitas. Preheat the oven to 450 degrees F.
When the pot has depressurized, carefully remove the lid and transfer the meat chunks to a baking sheet with a slotted spoon. They should be completely tender and falling apart. Place in the oven to cook for 5-8 minutes, or until the edges crisp up.
Serve however you desire - on AIP plantain wraps garnished with cilantro and avocado, or on a salad.
Recipe by Autoimmune Wellness at https://autoimmunewellness.com/instant-pot-pineapple-carnitas/