Preheat oven to 350°F. Place cupcake liners in a muffin pan.

In a medium size mixing bowl, sift together the flour, baking soda, baking powder and salt to incorporate well. You do not have to sift, just mix until well combined if you don't have sifter.

With a stand or hand mixer, cream together the butter, brown sugar and 1/4 cup of granulated sugar on medium high speed until light and fluffy. About 3-4 minutes.

Add egg and mix about a minute until well blended.

In a separate bowl, mix together the maple syrup and sour cream until well combined.

Add half of the dry mixture to the butter sugar and egg in mixer bowl. On low speed, add 1/3 of the syrup and sour cream mixture to bowl.

Add the dry ingredients in 2 more batches alternating with the sour cream mixture and mix until just blended.

In a small bowl, combine the remaining sugar, cinnamon and walnuts. Mix until well blended and walnuts and cinnamon sugar are well combined.

Scoop batter into liners in muffin tin about 3/4 full. Sprinkle tops of batter with nut and cinnamon sugar mixture, divide it so enough topping with be able to go on each muffin.

Bake for 25-30 minutes, depending on oven until golden brown. Test with a toothpick in center after 20 minutes.

When done, place muffin tin on wire rack to cool 5 minutes. Remove from tin and serve warm if desired. Great cooled also.

Drizzle with more maple syrup if desired.