1tablespooncornstarchmixed into 2 tablespoons water
Generously season flour with salt and pepper, then sprinkle the mixture onto the roast.
Heat oil on saute setting, until sizzling. Place floured roast into the pressure cooker and brown on each side.
Add the beef broth, vinegar, cooking wine (if using), garlic, thyme, bay leaves, salt, and pepper into the pot. Secure the lid and set for 75 minutes in high pressure. (For roasts more than 2 1/2 inches thick, cook for 85 minutes.) It will take about 10-15 minutes to come to pressure and begin the cooking time.
Do a quick release, then add potatoes, onion, and carrots. Secure lid and cook for 5 minutes on high pressure. Let pressure release naturally for 10 minutes, then do quick release.
Transfer roast and veggies to serving dish and cover with foil. Set cooker to saute and whisk in the cornstarch and water. Let simmer for about 2 minutes to thicken, then stir in the butter. Pour the gravy over the roast and veggies before serving.