Preheat oven to 325°F. Bring a large pot of water to a boil over high heat. Add cubed sweet potatoes, return to boiling and cook until soft, about 10 minutes.
Drain and transfer potatoes to the bowl of a food processor or stand mixer (or use a large bowl and a hand-held electric mixer).
Add coconut milk, cinnamon, maple syrup, vanilla, salt, and black pepper to potatoes. Mix on medium speed until smooth, scraping down sides of bowl once or twice. Taste and adjust flavours if desired. Add more maple syrup if you want it sweeter, more coconut milk to make it creamier or more cinnamon, salt and pepper to incorporate more flavour.
Transfer sweet potato mixture to a 9 x 9-inch baking dish. Sprinkle pecans evenly over sweet potato mixture.
Bake for 45 to 50 minutes, or until edges are slightly browned. Cool on a rack for 10 minutes. Serve warm.