Preheat the oven to 400 degrees to bake the sweet potato.  Wrap sweet potato in foil and place on a baking sheet once the oven is preheated.  Cook until sweet potato is soft when squeezed.  After cooling, peel the sweet potato and scoop out 1/2 cup of the sweet potato.  Set aside and lower the oven to 350 degrees for baking the muffins.

Line a muffin pan with cupcake liners. 

In a small bowl, sift together the dry ingredients: Flour, baking soda, baking powder, salt, cinnamon and all spice. 

In a medium bowl cream the brown sugar and room temperature butter.  Then blend in egg and vanilla. 

In another small bowl, combine the sweet potato and the heavy cream.  Once combined, add to the brown sugar mixture.

Slowly add the dry ingredients into the wet ingredients.  When the mixture is fully blended it will be thicker than cake batter, but not as thick as cookie dough. 

Scoop mixture into muffin pan until about halfway full. 

Bake for about 20 minutes.  Check with toothpick to see if they are ready! Serve warm or store for later.