1) Remove your roast meat from the roasting pan and pour off any fat.
2) Place over high heat (use 2 burners if necessary) and pour in the wine and stock to deglaze pan, scraping any bits stuck to the bottom of the pan with a wooden spoon or spatula.
3) 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 served as a sauce with your roast.
To create a gravy:
4) 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.
To make roux:
1) Melt butter in a small saucepan on low heat. Stir in flour and cook paste for 2 minutes, stirring constantly to prevent burning.
Cook's Note: Since all starch thickened sauces firm up as they cool, it's a good idea to make your gravy a little on the loose side.