1. Heat a 6- or 8-quart pressure cooker over medium-high heat. Add oil to cooker; swirl to coat. Sprinkle roast evenly with salt and pepper. Add roast to cooker; sauté 5 minutes, browning on all sides. Stir in 3 cups Pressure-Cooker Beef Stock and wine. Close lid securely; bring to high pressure over high heat. Reduce heat to medium or level needed to maintain high pressure; cook for 35 minutes. Remove from heat; release pressure through steam vent, or place cooker under cold running water to release pressure. Remove lid; add thyme sprigs and next 6 ingredients (through onion). Close lid securely. Return to high pressure; cook 1 minute. Remove from heat; release pressure through steam vent, or place cooker under cold running water to release pressure. Remove lid; let stand 5 minutes. Remove roast; slice roast thinly, and place on a platter. Remove vegetables from cooker using a slotted spoon, and place on platter with roast. Cover and keep warm.
2. Strain cooking liquid through a cheesecloth-lined sieve into a large bowl; discard solids. Bring cooking liquid to a boil over medium-high heat in a large, wide skillet; cook until reduced to 1 1/2 cups (about 15 minutes). Remove 1/4 cup cooking liquid from pan; add 2 tablespoons flour, stirring with a whisk. Return flour mixture to pan; cook 2 minutes or until slightly thick, stirring with a whisk. Serve with roast and vegetables. Garnish each serving with fresh thyme sprigs, if desired.