Preheat oven to 375°F.
In a small bowl or glass measuring cup, mix ½ cup of maple syrup, molasses, bourbon, cinnamon, cloves, and cayenne. Set aside.
In a small bowl, whisk together the cornstarch, sugar, salt, and pepper. Pour onto a rimmed cookie sheet.
Pat pork tenderloins dry with paper towels. Roll in the cornstarch mixture to thoroughly coat all sides, then shake the excess cornstarch off.
Heat oil in a cast iron over medium-high heat, then spray liberally with nonstick spray. Once hot, place tenderloins in the hot pan and sear on all sides for 8-12 minutes total. All sides should be browned well.
Add syrup mixture to the skillet and simmer for two minutes, flipping the tenderloins half way through. Remove 2 tablespoons of the glaze and set aside.
Place the skillet in the oven and cook for 12-20 minutes, until a thermometer stuck in the middle of the tenderloin reads 130°. Remove from the oven and use a silicone brush to rub the glaze from the pan over the tenderloins.
Return to the oven for another 2-4 minutes, until the thermometer reads 140-145°.
Remove tenderloins from the skillet and let rest uncovered on a cutting board for 10 minutes.
While the meat is resting, combine the remaining ¼ cup maple syrup, mustard, and reserved glaze in a small bowl.
After resting, slice meat and serve with maple mustard sauce.