Coffee Cake

1. Preheat oven to 350°F (177°C). Grease a 10 cup bundt or tube cake pan (see other pan options in faqs above) with nonstick spray. Make sure you don’t have pools of spray gathered at the bottom. Set aside.
2. Sift the flour, baking powder, baking soda and salt. Whisk all of them together. Set aside.
3. In another bowl, beat the butter for about 2 minutes until smooth and creamy. Add in the dark brown sugar and granulated sugar and beat until light and fluffy. Add in the eggs, yogurt and vanilla. Mix until thoroughly combined. 
4. Add half of the dry ingredients into the wet ingredients along with half of the buttermilk and whisk until combined. Repeat until all dry ingredients and buttermilk are added, starting and ending with the flour. The batter will be thick. Don’t overmix, it’s okay if a few streaks of flour remain. 
5. Pour two-thirds of the batter into the prepared cake pan. Carefully spread the batter in an even layer in the pan with an offset spatula. Bang it on the kitchen slab a few times down before continuing.

Pumpkin Spice Streusel

1. In a medium bowl, whisk together the flour, granulated sugar, brown sugar, and pumpkin spice.
2. Pour the melted butter into the dry ingredients and combine with a spoon or spatula. Allow the mixture to come to room temperature.
3. Once the mixture has firmed up, use your hands to break up the mixture into small, pebble-sized crumble pieces. 

Assembly

1. Using clean hands, sprinkle one-half of the crumble filling in an even layer on top of the batter.
2. Then add the final one-third of the cake batter on top of the crumble. It is easier to spoon the remaining one-third of the batter in little piles all over the crumble instead of pouring all of the batter in one mound.
3. Use the offset spatula to carefully cover the crumble layer. Put in the oven for about 25 minutes.
4. After 25 minutes, take out the pan and sprinkle the remaining one-half of crumble mixture on top of the cake. Put back in the oven for 10-15 more minutes, checking often.
5. The cake is done when a toothpick comes out clean and with a few crumbs remaining. Let the cake cool in pan for 15 minutes before carefully removing from the pan. Cool on a wire rack until completely cool before adding glaze.

Maple Glaze

1. While the cake is cooling, whisk together the sifted powdered sugar, maple syrup and milk. Start with 1 tablespoon of milk at a time because you want the glaze to be very thick.
2. Drizzle the glaze on top of the cooled cake and allow to set for 10 minutes before slicing.