1. Preheat oven to 400 degrees F. Spray a 12-cup muffin pan with vegetable cooking spray.
2. Prepare the streusel. In a small bowl, stir together flour, brown sugar, cinnamon, and salt. Cut butter into small cubes and mix in using a fork, pastry blender, or your fingers until the topping resembles large crumbs; refrigerate.
3. Prepare the muffins. In a medium bowl, stir together flour, baking soda, baking powder, cinnamon, nutmeg, and salt.
4. In a separate large bowl, mix together sweet potato, honey, and oil. Add eggs, buttermilk, and vanilla and whisk to combine thoroughly. Add flour mixture to the liquid mixture and stir until just combined. Stir in the raisins and walnuts, if using.
5. Evenly divide the batter among the prepared muffin cups. Sprinkle the streusel topping evenly over tops and bake until tops spring back when touched lightly with your finger, about 14 to 17 minutes. Remove from the pan and cool on a rack. Serve warm or at room temperature.
Recipe courtesy of Linda Melone
Source: Hannaford fresh Magazine, November - December 2012