Preheat oven to 325°. Place vegetables on bottom of a shallow roasting pan. Mix 2 tablespoons flour, bay leaf, thyme, and 1 teaspoon each salt and pepper; rub over roast. Place roast on top of vegetables, fat side up. Add 2 cups water to pan.

Roast, uncovered, 1-½ hours. Sprinkle brown sugar over roast. Roast 15-20 minutes longer or until a thermometer reads 140°. (Temperature of roast will continue to rise another 5-10° upon standing.)

Remove roast to a platter. Tent with foil; let stand 15 minutes before slicing.

Strain drippings from roasting pan into a measuring cup; skim fat. Add enough water to the drippings to measure 1-½ cups.

In a small saucepan over medium heat, whisk remaining flour and ⅓ cup water until smooth. Gradually whisk in drippings mixture and remaining salt and pepper. Bring to a boil over medium-high heat, stirring constantly; cook and stir 2 minutes or until thickened. Serve roast with gravy.