Make the glaze: Put garlic and rosemary in a small bowl. Add the vinegar, honey, olive oil, mustard, and salt and pepper, to taste, and stir to combine.
For the pork: Slice the tenderloin into 1-inch thick medallions (rounds). Cover the bottom of a medium skillet with a light film of canola oil and heat over medium-high heat until hot. Add the pork slices in 1 layer, season with salt and pepper, and sear for 1 minute. Turn and sear for 1 more minute, until lightly browned. Transfer the slices in 1 layer to a shallow baking dish.
Pour the glaze over the slices and turn them to coat.
Roast for 8 to 10 minutes, until a thermometer inserted reaches 140 degrees F for medium. Remove from the oven and keep warm, loosely covered until ready to serve.
To serve place pork medallions on a platter and spoon the balsamic-honey glaze over them. Garnish the platter with the rosemary sprigs.