streusel apple coffee cake

i baked this a few nights ago for a company xmas party. we were about to watch black swan and i wanted to bake it before we did because i didn't have any time to bake it before the party. i used a ton of grease on the pan and then floured it because i didn't want the cake to stick. well that did really work. when it was done i follow the directions to pop it out and the bottom half disconnected from the top where the streusel is. so i just left it in the tube pan and said fuck it, it still tastes good. how can u go wrong with a ton of streusel? i really need to work on my presentation for baked goods. anyways, i took it to this party and most people chose to eat individually packaged cobblers and cookies because they didn't want to cut into this messy cake. oh wells, more for me.

1 1/2 cups packed light brown sugar

3/4 cup all-purpose flour

1/2 cup butter, chilled and diced

2 teaspoons ground cinnamon

1 cup chopped walnuts

3 1/4 cups all-purpose flour

1 1/2 teaspoons baking powder

3/4 teaspoon baking soda

3/4 cup butter, room temperature

1 1/2 cups white sugar

3 eggs

2 teaspoons vanilla extract

16 ounces plain low-fat yogurt

2 Granny Smith apples - peeled, cored and finely diced

Directions

Preheat oven to 350 degrees F (175 degrees C). Grease and flour a Bundt cake pan.

To make streusel: In a medium bowl, mix brown sugar, 3/4 cup flour, and cinnamon. Cut in the butter with a fork until crumbly. Stir in walnuts.

In a medium bowl, stir together 3 1/4 cups flour, baking powder, and baking soda. In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, mixing well after each. Then stir in the vanilla and yogurt. Gently stir in the flour mixture just until blended.

Pour 3 cups of the batter into the Bundt pan, sprinkle with 1/4 of the streusel, and layer with apples. Sprinkle with 1/2 the remaining streusel. Pour in the remaining batter, and top with the remaining 1/4 streusel. Lightly pat the top layer of streusel so it sticks to the cake batter.

Bake 50 to 60 minutes in the preheated oven, or until a toothpick inserted in the center comes out clean. Cool in the pan on a wire rack 15 minutes. Place cookie sheet over pan and carefully invert both. Remove Bundt pan, and let the cake cool completely.