In the pressure cooker, brown the diced bacon over medium heat. Once cooked, drain the bacon and set aside until later. Reserve 2 tablespoons of the bacon fat in the pot.
Combine the flour, salt, pepper, and garlic powder in a small dish. Coat the meat with the flour mixture.
Over medium heat, brown the meat in the reserved bacon fat. Add the quartered mushrooms, carrots, and onions to the pot and cook for a minute or two.
Stir in the wine, beef stock, mustard, and thyme. Lock the lid in place, bring to HIGH pressure. Stabilize the pressure and cook for 30 minutes.
When done, release the pressure, and add the reserved bacon. Serve alone or with mashed potatoes.