Preheat the oven to 400°F. Lightly grease 10 cups of a standard size muffin tin and set aside.
Make the streusel topping. In a small bowl, whisk together the chopped pecans, coconut sugar, salt, and cinnamon. Add the vegan butter to the bowl and mix it in with your fingers, breaking up the bits of butter and working them into the sugar and pecans. Once you have a sandy and crumbly texture, and the streusel sticks together when you pinch it with your fingers, set aside in the refrigerator.
In a large bowl, combine the spelt flour, cinnamon, baking powder, baking soda, and sea salt. Stir with a spatula to evenly mix.
In an upright blender, combine the mashed and cooked sweet potato, maple syrup, coconut oil, non-dairy milk and vanilla. Blend on high until totally smooth and creamy.
Pour the puréed sweet potato mixture into the large bowl with the spelt flour mixture. Use your spatula to get all of the sweet potato mixture you can out of the blender. Gently stir and fold everything together until JUST combined.
Divide the muffin batter evenly among the 10 prepared muffin cups. Grab the pecan streusel from the fridge and divide it evenly among the tops of the muffins. Really press it into the muffin batter with your fingers.
Bake the sweet potato muffins for 18-20 minutes, or until the tops are domed and slightly darkened and a paring knife/cake tester inserted into the middle of one comes out clean. Let the muffins cool completely before enjoying!