Remove roast from pan and pour off any fat, reserving 2 ounces. Place roasting pan 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 the gravy, heat the reserved fat over medium-high heat in a medium saucier. Add the flour all at once whisking vigorously. When the mixture thins and starts to bubble, reduce the heat to low and cut back on the whisking. Cook until you smell a toasty aroma, then cook 2 minutes more, stirring occasionally. Allow the roux to cool to room temperature.
Whisk a quarter of the jus into the cooled roux. Return the heat to high and add all but 1/4 cup of the liquid. Cook until a simmer has been reached, which will result in a smoother sauce, but not a thicker one. Since starch-thickened sauces thicken as they cool, make your gravy a little on the loose by adding the last 1/4 cup of liquid. Serve over the warm roast.