In the same skillet, brown the roast on all sides in the remaining oil, then place on a baking sheet. Set the skillet aside to reserve the cooking juices for the sauce. Brush the roast with the Dijon mustard. Season with salt and pepper. Add the vegetables and garlic cloves to the pan. Bake for 50 minutes or until a thermometer inserted in the meat reads 122°F (50 °C).