Remove roast from pan and pour off any fat. Place over high heat (use 2 burners if necessary) and deglaze pan with wine and broth, scraping any bits stuck to the bottom of the pan with a wooden spoon or spatula. Once these solids are dissolved, pour liquid into a saucepan and add the bay leaf and peppercorns. Reduce for 5 minutes over high heat or until reduced by 1/3.
At this point you basically have a jus which could be used to sauce your roast. To create a gravy, reduce the heat to medium and whisk in 2 tablespoons of white roux. Return to a simmer, whisking constantly. Continuing to cook once a simmer has been reached will result in a smoother sauce, but not a thicker one.
Since all starch thickened sauces thicken as they cool, it's a good idea to make your gravy a little on the loose side.
Recipe courtesy of Alton Brown