Pour chicken broth into the bottom of the Instant Pot.
Season pork tenderloin with salt and pepper. Place in the bottom of the Instant Pot.
In a small bowl, combine syrup, garlic, mustard, honey, brown sugar, vinegar, and thyme. Pour over the pork.
Put your lid on the pot and move the valve to SEALING (not venting). Press the PRESSURE COOK (or MANUAL) button and set timer for 5 minutes.
When timer is done, let pressure do a NATURAL RELEASE (it will take about 20 minutes, maybe longer).
We prefer to let the meat sit in the Instant Pot on the "keep warm" setting for a couple of hours and it will literally fall apart, but make sure that you at least let it do a natural release for 20 minutes when it's done cooking.
Remove pork to a plate and cover with foil to keep warm. Press SAUTE button and bring liquid in the Instant Pot to a boil. Simmer for 5 minutes. In a small bowl, mix together cornstarch and cold water, then whisk into liquid left in Instant Pot. Cook for 1 minute longer or until liquid has thickened up. Slice the pork and serve with the thickened juices.
Slow Cooker Instructions
Sprinkle tenderloins lightly with salt and pepper.
Place pork in a slow cooker sprayed with non-stick cooking spray.
Combine syrup, garlic, mustard, honey, brown sugar, vinegar, and thyme. Pour over the pork.
Turn pork to coat thoroughly.
Cover and cook on LOW for 7 to 8 hours, or on HIGH for 3 to 4 hours.
Remove pork to a plate and cover with foil to keep warm.
Pour the juices into a saucepan and bring to a boil over medium heat.
Simmer for 5 minutes.
Combine the cornstarch and cold water; whisk into the reduced juices and cook for 1 minute longer.
Slice the pork and serve with the thickened juices.
Notes
Fresh brown sugar provides some amazing flavor. If you want to make your own, take a look at this simple Brown Sugar recipe from The Kitchn.