Prepare the filling by combining the filling ingredients in a small bowl. Stir to combine well. Set aside. Preheat the oven to 350°F.
For the cake, cream the butter and sugar in a mixing bowl, using a hand mixer on medium speed for 45 seconds. Scrape the sides of the bowl with a rubber spatula. Add the eggs and beat for 30 seconds. Scrape the sides of the bowl. Add the coffee, vanilla extract, and sour cream. Beat on low speed for 30 seconds, until well creamed. Scrape the sides of the bowl. In a separate mixing bowl, sift together the flour, baking soda, and baking powder. Pour the creamed mixture over the top of the flour mixture, scraping the bowl well. Mix on low speed for 45 seconds just to combine, stopping to scrape the sides of the bowl.
Prepare a 10-cup Bundt pan, either by thoroughly spraying with nonstick cooking spray or greasing with shortening and flouring the pan. Pour in half the batter. Sprinkle half the filling evenly over the top of the batter. Pour the remaining batter evenly over the filling. Use a rubber spatula to scrape the batter from the bowl and smooth the batter. Sprinkle the remaining filling evenly over the batter.
Bake in the center of the oven for 50-55 minutes, until a cake tester inserted in the center comes out clean. Remove the cake from the oven and let it cool in the pan for 5 minutes, then turn it out onto a plate. Serve warm or cooled to room temperature, drizzled with a glaze, frosted with Buttercream Frosting, or sprinkled with powdered sugar.