Ingredients
For the streusel topping
1 1/2 tablespoons finely grated orange zest
1/3 cup packed light brown sugar
1/2 teaspoon ground cinnamon
4 tablespoons cold butter
1/2 cup flour
For the muffin batter
1/2 cup chopped candied ginger
1/4 cup butter, melted, or vegetable oil
1/3 cup molasses
1/2 cup packed light brown sugar
1 cup pureed roasted sweet potato
2 eggs
6 tablespoons plain yogurt mixed
2 tablespoons milk
1 3/4 cups flour
1 1/2 teaspoons baking powder
1 teaspoon baking soda
1/2 teaspoon salt
1 teaspoon ground cinnamon
Directions
Preheat the oven to 375F.Line a 12-cup muffin pan with liners.
To make the streusel, combine all the topping ingredients in a bowl and rub together with your fingers until it looks like coarse sand. Set aside.
To make the muffin batter, in one bowl, mix the ginger, melted butter or oil, molasses, brown sugar, sweet potato, eggs, milk and yogurt until smooth. In a second bowl, whisk together the flour, baking powder, baking soda, salt, and spices. Combine the dry and wet ingredients, stirring gently until just blended. Let sit for 30 minutes (this is very important, otherwise you will have flat and unsightly muffin tops).
Spoon the batter into the prepared muffin pan. Sprinkle the streusel topping evenly over the batter and press it in gently. Place on the middle rack of the oven and bake until lightly browned, 23-25 minutes. Remove to a wire rack and cool at least 15 minutes before devouring.