If you like your gravy very thick, I've got you covered! This recipe for beef tips uses cornstarch to thicken the sauce into a gravy. You can 1) use more cornstarch or 2) cook the gravy longer. The gravy also thickens as it cools. Adding the optional sour cream listed in the recipe will also thicken the gravy in addition to adding an overall creaminess to the pressure cooker beef tips.