Cinnamon Streusel Sour Cream Cake

Directions

1. Preheat the oven to 375°,F. Grease and flour a 9 1/2" tube pan or a 9" x 9" pan. Beat together the butter, sugar until almost white in color. Add eggs one at a time then vanilla and balsamic vinegar. In a separate bowl, mix the flour, baking powder, baking soda, and salt. Add the flour mixture to the butter mixture alternately with the sour cream, stirring after each addition.
2. Combine all the topping ingredients, stirring until evenly crumbly. Spread half the batter in the pan, and sprinkle with half the topping mixture. Repeat with the remaining batter and topping.
3. Bake the coffeecake for 30 to 40 minutes, or until a toothpick inserted into the center comes out clean, or with just a few moist crumbs sticking to it. Glass pans may take an additional 5 to 10 minutes to bake through completely. Remove the cake from the oven, if you've baked it in a tube pan, wait 10 minutes, loosen the edges, and carefully turn it out of the pan. Place the cake right-side up (topping up) on a plate to serve. If you've baked the cake in a 9" x 9" pan, just serve it right from the pan. Serve the cake warm or at room temperature. Wrap the completely cooled cake airtight, and store at room temperature for several days: freeze for longer storage.
4. Place metal bowl and metal whisk in freezer for 10-15 minutes (if using electric mixer this step isn&rsquo,t as necessary). Place sugar and vinegar into a mixing bowl, add heavy cream. Whisk until cream reaches stiff peaks.