Add the roast and brown on all sides, 3 to 4 minutes total. Transfer the roast to a platter. Add the onions to the pressure cooker and cook until tender, 3 to 5 minutes. Return the roast to the pressure cooker along with the carrots, stock, garlic, thyme and bay leaf.Cover, set the pressure to high and cook for 1 hour and 20 minutes.dd the roast and brown on all sides, 3 to 4 minutes total. Transfer the roast to a platter. Add the onions to the pressure cooker and cook until tender, 3 to 5 minutes. Return the roast to the pressure cooker along with the carrots, stock, garlic, thyme and bay leaf.