Preheat oven to 350°F. Generously spray a bundt pan with non-stick spray or brush thoroughly with vegetable oil and dust lightly with flour.
filling
In a small bowl, combine filling ingredients until blended. Set aside.
cake
In a medium bowl, whisk together flour, baking powder, baking soda and salt until blended. Set aside.
In a large mixing bowl, cream together butter and sugar until light and fluffy, scraping down sides once or twice. Add yogurt, eggs, vanilla and blend until smooth, scraping down sides as needed.
Add flour mixture and beat just until the flour is combined. Fold in chocolate chips.
Spread half of the cake batter in the prepared pan. Sprinkle filing on top, trying to keep it from touching the pan (it will stick). Spread the remaining batter over the filling.
Bake at 350° for 30-40 minutes, until a toothpick inserted in the center comes out clean.
Let cool for 10 minutes on a cooling rack. Gently slide a spatula along the sides and center of the pan. Shake the pan gently to loosen the cake. Place wire rack on top of the pan and invert.
Let cake cool completely. Before serving add cocoa powder or powdered sugar, or both, to a small metal sieve and dust the cake. Slice and serve.