To make your Maple Coffee Cake, start by preheating your oven to 350 degrees and spraying a 9 x 9 baking pan with non-stick spray. Set aside and begin making your pecan streusel. Add brown sugar, flour, pecans, cinnamon and melted butter to a small bowl and stir to combine. Set aside.
Then begin whisking together your flour, cinnamon, baking powder, baking soda, salt and brown sugar in a large mixing bowl. In a separate bowl, add the maple syrup, vegetable oil, milk, eggs, maple extract and sour cream and mix until well combined. Then add the wet ingredients to the dry ingredients and using a large mixing spoon, mix ingredients together until just incorporated. Do not overmix and do not break out the electric beater.
Pour half of your cake mix into your prepared pan and even out with the back of the spoon. Sprinkle about 1/3 of your pecan struesel evenly on top of your cake mix and then spoon the remaining batter evenly on top of your pecan struesel layer and even out again with the back of the spoon. Sprinkle the remaining pecan struesel evenly on top of your cake and bake for 35 - 40 minutes. Remove from the oven and let cool on a baking rack for 20 minutes before serving.
While your cake cools, make the icing. Combine powdered sugar, maple syrup, maple extract and milk to make an icing that can be drizzled on top. Too thin, add more powdered sugar. To thick, add a bit more milk. Drizzle maple icing on top of your Maple Coffee Cake and serve while warm. Leftovers can be covered and stored in the refrigerator for up to 3 days.