Our all-time favorite coffee cake. The boys prefer it without the pecans, but I love the texture of the nuts as part of the filling. Either way, it's a wonderful, moist and luscious cake.
Preheat oven to 350 degrees F. (325 degrees F. if using a glass baking pan).
In a large mixing bowl, combine the cake mix ingredients using an electric mixer to beat the ingredients for 2 minutes, scraping bowl half way through. Meanwhile, in a medium mixing bowl, combine the filling ingredients and reserve.
Pour half of the prepared cake batter into a greased 9 x 13 pan. Sprinkle the prepared filling mixture over the batter, then use a butter knife to swirl the filling into the batter. Now, pour the remaining cake batter over the top of the filling.
Bake the cake, uncovered, on the center rack of the preheated oven for 25-30 minutes, or until a cake tester or knife inserted into the center of the cake comes out clean.
While the cake is baking, combine the icing ingredients in a medium mixing bowl and whisk until smooth.
When the cake is removed from the oven, immediately pour the prepared icing over the hot cake, then cover the cake pan tightly with foil, letting the cake cool completely while covered.