Step 1: Get your liquid ready. Liquid base gravy starts with a liquid. This can be the juices from a roast, chicken, turkey, ham or broth from a can or water and boullion. I'm using turkey juices. You can strain your juices if you don't like chunks in your gravy. I like mine with everything in it, so I just pull the meat out of the roasting pan and make the gravy right in the pan. If you had a fatty piece of meat, skim some of the fat off the top of the juices with a spoon. Then turn on the burner (this roaster spans 2 burners, so I turn them both on) and heat the juices up. Stir and scrape the good scrappy stuff off the bottom and sides of the pan. Here's the pan of yummy turkey juice:
Step 2: This is optional--sometimes you need it, sometimes not. If you don't have a lot of broth or it is really concentrated, add some water. If I'm making mashed potatoes and they're done, I add potato water to the gravy. Free starchy water with potato goodness in it that otherwise would go down the sink. (Okay, the picture didn't come out so good--hard to get a nice picture when your flash goes off and it's steamy.)
Step 3: Get a cup of COLD water. You can use a glass or plastic measuring cup or just a mug. You don't want anything too tall since you'll be stirring in it. Hot water makes lumps out of the cornstarch.
Step 4: Put a couple of heaping tablespoons of cornstarch into the cup. How much cornstarch you will need will depend on the amount of juice you have. It'll take more starch to thicken up if it's a big ol' pot o' broth. Start with a couple heaping scoops--you can always add more. Stir it up.
Step 5: Pour the cornstarch/water mixture in the boiling broth. Stir it in and bring back to a boil. If, when it's boiling, it's not thick enough, repeat steps 3-5. If it's too thick (I've made batches before that turned out as thick as jelly--oops!) add some water and stir it in.
Step 6: Once it's gravy consistency, season to taste. Some gravies need lots of salt, others don't. It will depend on what you started with. If it's going over mashed potatoes, make it a little saltier than you think it should be (the potatoes counteract some of the saltiness). I've fixed up gravy I thought tasted perfect and then had to salt it once it was on the potatoes. Yummy, yummy, yummy gravy. Oh yeah, make sure cornstarch is on your food storage list :)