Cut slits into the roast and insert slices of garlic, placing the pieces evenly around the whole roast, Rub with 1 Tbsp mustard and sprinkle with thyme. Place onto a roasting rack and top roast with the slices of bacon. Roast at 325 degrees for 1 1/2 to 2 hours.
Remove roast from pan. Pour drippings into a small skillet.
Whisk in remaining tsp of mustard and heat to boiling. Continue to boil util the juices are shiny and have thickened. Spoon sauce over roast and serve.