In a small bowl mix together the garlic, rosemary, Dijon mustard, maple syrup, salt, and several healthy cracks of black pepper from a pepper grinder. Use your hands to coat the 2 tenderloins with the marinade. If you are marinating the pork a few hours ahead of time, wrap and refrigerate it until 1/2 hour before you are ready to cook.
Just before cooking, season the outside of the tenderloins with an additional 1/2 teaspoon kosher salt. Heat 2 teaspoons of the oil over high heat in an oven-proof skillet large enough to comfortably accommodate both tenderloins. Add the meat to the pan and cook on all sides until nicely browned. This will take a few minutes per side.
The USDA recommends cooking pork to 145 degrees