Prepare the ingredients. Season the pork loin with salt and pepper. Finely chop the onion, leek, and garlic.

Keep the onion and leek separate from the garlic. Heat the olive oil in the pressure cooker over medium heat. Sear the pork loin on all sides until well browned. Once browned, set it aside on a plate and keep warm.

Sauté the onion and leek until softened, scraping up any browned bits from the bottom of the pot as they release their juices.

When the vegetables are translucent, add the garlic and thyme. Cook until fragrant, about 1 minute. Add the mushrooms and cook for 5 minutes.

Pour in the beer, bring to a boil, and let the alcohol evaporate, scraping up any bits stuck to the bottom. Add the mustard. Mix well, then add salt, pepper, and the cup of water.

Place the pork loin on top of the vegetables and cover the pressure cooker. Once it reaches pressure, cook for 45 minutes. Let it cool slightly, then remove the meat. Discard the thyme sprigs.

Slice the meat. I use an electric knife for speed. Boil the sauce until it thickens to your liking. Return the meat to the sauce, heat through, and serve with your choice of side—rice, baby potatoes, mashed potatoes, or steamed vegetables are all good options.