1. Heat oven to 400°F Season beef with salt and pepper. Heat oil in skillet just until it begins to smoke. Sear the tenderloin, browning on all sides, about 8-12 minutes. Remove beef from skillet and place on foil-lined baking sheet. Roast in oven, 8-10 minutes for medium rare. Let rest 10 minutes before slicing.
2. Slice potatoes 1/2-inch thick and place in a steamer basket over a pot of water. Cover and turn heat to high, bringing water to a boil for 7-10 minutes. Potatoes should pierce easily with a fork when cooked. Saute bananas in skillet with 1 tablespoon of butter and the ginger. Add orange juice and cinnamon. Reduce to a paste by stirring and mashing the bananas. Mix potatoes with the banana mixture. Add 3 tablespoons butter and season to taste with salt. Mash until potatoes are a smooth, thick consistency.
3. For the sauce, combine the ingredients and season to taste with salt.
4. Cut beef into 1/2-inch slices. Spoon mango barbecue sauce on top. Serve with sweet potatoes.
How to make the mango chutney: In a medium saucepan, combine 1 1/4 cups diced mangoes (about 2 small mangoes), 1/2 tablespoon peeled and minced fresh ginger, 1 minced jalapeno (membrane and seeds removed), 1 clove garlic (minced), 1/8 teaspoon kosher salt, 1/4 cup cider vinegar, 1/4 cup firmly-packed brown sugar and 1/4 cup raisins. Bring mixture to a boil. Reduce heat and simmer, stirring frequently, about 25 minutes or until mixture thickens. Let cool.