01 - Preheat oven to 400°F and line a baking sheet with parchment paper or lightly oil a roasting pan.
02 - Whisk together maple syrup, Dijon mustard, whole grain mustard, apple cider vinegar, olive oil, minced garlic, salt, and pepper in a small mixing bowl.
03 - Pat the pork tenderloin dry with paper towels and position it on the prepared baking sheet.
04 - Brush pork thoroughly with half of the glaze mixture.
05 - Roast in the preheated oven for 15 minutes.
06 - Brush the tenderloin with remaining glaze.
07 - Continue roasting for 8 to 10 minutes, or until pork reaches an internal temperature of 145°F.
08 - Remove from oven, tent loosely with foil, and let rest for 5 minutes.
09 - Slice the rested pork and arrange on a serving platter. Garnish with chopped parsley if desired.