Buttermilk coffee cake is a soft, moist, fluffy and buttery vanilla cake layered with an easy cinnamon streusel. It's topped with cinnamon streusel and a creamy vanilla glaze.
In a large bowl, whisk together the flour, brown sugar, granulated sugar and ground cinnamon for the streusel topping. Work in the cold butter cubes until a sand like texture develops.
In a large mixing bowl, beat butter and sugar together until light and fluffy. This takes about 2-3 minutes on medium speed. On low, beat in the eggs and vanilla extract until smooth and well combined. Alternate adding dry ingredients and buttermilk to the wet.
Evenly spread half coffee cake batter into the prepared pan. Use ? to ½ of the streusel to top the first layer of cake. Repeat with a second layer of coffee cake and finish with the remaining cinnamon streusel.
Bake the coffee cake for 35 - 45 minutes or until a toothpick inserted into the center of the coffee cake comes out clean or with a few moist crumbs. Cool the pan in the pan for 15-20 minutes.
Make the vanilla glaze by whisking powdered sugar with vanilla extract and milk or heavy cream. Top the crumb cake coffee cake with the glaze, slice and enjoy!