Add sherry, whole garlic cloves and broth to the vessel of your Instant Pot.

Place pork belly fat side up in the sherry-broth. Top with salt and rosemary.

Close and lock the lid. Set the pressure to HIGH and time to 80 minutes.

When time is up, do a manual or natural release.

Place duck fat in cast iron pan. Transfer to the oven and preheat to 400 F. You want the pan to get hot, but you don't want the oil to smoke.

Place the pork belly in the preheated cast iron pan with the duck fat, fat and rosemary side down. Turn oven down to 375 F.

Return to oven and roast for 10 minutes. Flip and roast another few minutes to desired crispness.  

Transfer to a cutting board to cut into pieces and serve sprinkled with some high-quality sea salt, like Maldon