Place your peeled and cubed sweet potatoes into a large pot of water. Bring the water to a boil and cook the potatoes for about 15 to 20 minutes, or until they are very tender when pierced with a fork. Drain the water well and return the potatoes to the pot or a large mixing bowl.
While the potatoes are still warm, mash them using a potato masher or an electric mixer until they reach your desired consistency. Add the melted butter, maple syrup, whole milk, beaten eggs, alcohol-free vanilla extract, and salt. Whisk everything together until the mixture is smooth, creamy, and well combined.
In a separate small bowl, combine the brown sugar, all-purpose flour, and chopped pecans. Use a fork or your fingers to work the cold, cubed butter into the mixture until it looks like coarse crumbs.
Preheat your oven to 350 degrees Fahrenheit. Lightly grease a 9 by 13 inch baking dish with a bit of butter. Spread the sweet potato mixture evenly into the dish, smoothing the top with a spatula. Sprinkle the pecan crumble evenly over the entire surface of the potatoes.
Place the casserole in the center of the oven and bake for 35 to 40 minutes. You will know it is ready when the potato mixture is set and the pecan topping has turned a beautiful golden brown and smells toasted. Let the dish rest for a few minutes before serving to allow the flavors to settle.
