Preheat oven to 350-f degrees. Prepare a 9-inch round cake pan with a circle of parchment paper in the bottom and grease the sides with butter or cooking spray.
To prepare the streusel, add flour, brown sugar, cinnamon, other spices and melted butter to a medium sized bowl and mix with a fork until all ingredients are incorporated. Set aside.
To make the cake batter, beat sugar and butter until light in color and fluffy, 3-4 minutes. Add pumpkin puree, milk and sour cream and mix until well incorporated. Add egg and vanilla extract and mix until smooth. Combine flour, baking powder and spices in a separate bowl. Add dry ingredients to batter and mix until smooth.
Spread half of the cake batter into the bottom of the cake pan. Top batter with about half of the streusel mixture. Spread remaining cake batter over streusel. Sprinkle chopped pecans and remaining streusel over the top of the cake batter.
Bake for 24-26 minutes, or until a toothpick inserted comes out with only a few crumbs. Remove cake from oven and allow to cool in the pan for about 5 minutes. Then remove to cooling rack to finish cooling.
To make the glaze, combine powdered sugar, maple extract and milk in a small bowl and whisk until smooth. You can always add a little more milk or sugar, if needed. Drizzle the glaze over the coffee cake. Optional garnish: Sprinkle with chopped pecans.