For the Pork Tenderloin:
Preheat the oven to 350 degrees.
Wash and pat dry the pork tenderloin. Remove any excess membranes (silver skin). Season with salt, pepper, and the dried sage.
Heat a large pan such as a dutch oven over a medium burner.
Add 2 tsp olive oil to coat the pan.
Brown the pork for 3 minutes on the fronts and backs and 2 minutes on the sides. If you have trouble keeping the pork on their edges, you can prop it against the pan, or use long-handled tongs to keep them in place.
Turn off the burner, and transfer the browned pork loins to an oven proof dish baking dish. Insert a digital meat thermometer into the thickest part of the loin, and cook in a 350-degree oven until the loins reach 145 degrees, (about 20 min). Allow the loins to rest for 10 minutes; the temperature will continue to rise out of the oven, (mine reached 158 degrees).
For the Balsamic Dijon Sauce:
If the pan that you used to brown the pork has blackened char marks on the bottom, you should wash your pan before continuing, otherwise the sauce will have a burned flavor. However, if you just have some yummy browned bits on the bottom, you can continue cooking with the same pan.
Reheat the pan over a medium burner. Add another Tbs of olive oil and sauté the chopped shallots until they begin to soften and turn translucent about 3 minutes.
Add the chicken broth, balsamic vinegar, Dijon mustard, maple syrup, and fresh sage leaves. Stir and deglaze the pan. Bring the mixture to a boil, then lower the heat to a simmer.
Add the fresh sage leaves and continue simmering. Reduce the mixture by 2/3, stirring often. Discard the fresh sage leaves. Taste the sauce and adjust the salt and pepper.
Slice the pork loins width-wise on a bias, and return and any pork juices that collected on the cutting board and the baking dish to the saucepot, and stir.
Serve the pork tenderloin topped with the Balsamic Dijon Sauce.