Season tenderloin with salt and pepper on both sides. Place a large ovenproof skillet over high heat, melt the butter and sear tenderloin on all sides. Place in oven and cook to desired doneness or until an instant-read thermometer inserted registers 125 degrees F for medium rare, about 30 to 40 minutes depending on the thickness of the tenderloin. Let the meat rest for 10 minutes before slicing. Serve with the sauce.
Rum-Red Chili Sauce:
Melt the butter and olive oil in a medium saucepan over medium high heat. Add the shallots and garlic and cook until soft. Add the rum and reduce to 1/4 cup. Add the stock, bring to a boil and reduce the heat. Whisk in the remaining ingredients and simmer until reduced to 2 cups.