For the cake

1. Preheat oven to 350°F. Line a 9×13-inch pan with parchment paper. Allow the butter, eggs and sour cream to come to room temperature.
2. In a stand mixer, cream the butter and sugar together for several minutes until light and fluffy. Next, add the eggs one at a time beat until well incorporated, scrape down the sides of the bowl as needed.
3. Then add sour cream and vanilla extract and beat until well incorporated.
4. In a separate bowl, combine the remaining dry ingredients and slowly add to the batter, beating until incorporated. Then use a spatula and mix by hand until well combined. 
5. To prepare the streusel, mix the dry ingredients and combine with the melted butter, mix together until well blended. 
6. Pour half of the batter into the bottom of the pan and spread evenly. Then sprinkle half of the streusel over the batter. Top with remaining batter and streusel.
7. Bake at 350°F for 55-60 minutes. If the top of the cake is browning too quickly tent with aluminum foil for the last 15-20 minutes of baking. Check the cake for doneness by inserting a toothpick into the center of the cake. If the toothpick comes out clean, then the cake is done. Allow to cool completely or serve slightly warm. 

For the glaze

1. To prepare the glaze, slowly add the liquid ingredients to the powdered sugar and stir until desired consistency is reached. For a thicker glaze, add less liquid. If the glaze is too thin, add additional powdered sugar. Drizzle over finished coffee cake prior to serving.