Place raw pork lon roast on a cutting board and make 1-inch cuts all over the surface of the roast.
Wash hands again. Have ready the Dijon mustard and pepper. Combine the thyme, rosemary, and garlic in a mortar and pestle. Mash the garlic with the herbs and press inside the holes on the surface of the pork.
Using a silicone brush, paint a thin layer of Dijon mustard onto the exterior of the pork roast, and sprinkle all over with black pepper.
Wash hands again, and select the saute function for 3 minutes on the Instant Pot. After a minute or two when the oil is shimmering, place the fat cap side of pork roast into the oil. Cook for about 3 minutes, or until well-browned. (Do not let the roast burn, the heat on saute can function be difficult to control. Remove from pot if it browns too quickly and lower the saute heat.) Remove the roast to a plate and deglaze the pot with the vegetable broth.
Turn the Instant Pot off and place the trivet inside. Put the roast on the trivet with the fat cap facing up. Put the lid on and select the Pressure cook function for 18 minutes. At the end of the time, do not quick-release the pressure. The float should naturally drop after a bit. Remove the roast after 12 minutes and check the temperature with an instant-read thermometer. It should be between 145 F and 150 F.(If the roast is not quite at 145 F, return it to the pot and cook for an additional 3 minutes. The pot will pressurize very quickly. Use quick-release venting and remove the roast as soon as the float drops.)Place the roast on a clean cutting board and cover with foil.
While the pork loin rests and absorbs its juices, make the gravy by whisking the flour and water together into a smooth slurry. Turn on the Instant Pot saute function. Slowly whisk the slurry into the juices in the bottom of the pot. As the mixture comes to a boil, it will thicken. At this point, turn the pot off and remove the inner liner so that the gravy does not become overly thick or dry out.
Slice the roast and serve the gravy on the side. Enjoy!
Notes
Inserting the herb-garlic mixture into pockets all over the surface of the roast (don't forget the ends of the meat) imparts tremendous flavor, so you won't need much salt. The Dijon mustard coating provides enough salt for the meat, and commercial vegetable broth gives the gravy enough sodium.🧂 If you use homemade broth, you may want to season the gravy with ¼ teaspoon of salt. Start with ¼ teaspoon and taste before adding more, if needed.For gluten-free gravy, use one or two Tablespoons of cornstarch instead of a flour-water slurry. Combine the cornstarch with water to dissolve before adding to the juices to thicken them.This hearty entree serves four people generously; you could easily stretch it to feed six, especially if one or two of those are pint-size (children).This entree is low-calorie and lean, but warm and filling. ♨