Buttermilk Pecan Sticky Bun Coffee Cake

Source: Savour Fare

Buttermilk Pecan Sticky Bun Coffee Cake
Adapted from the Fannie Farmer Baking Book by Marion Cunningham.

For cake:
3/4 cups butter
1 1/2 cups granulated sugar
2 Tbsp molasses
1 1/4 cups buttermilk
1 Tb vanilla
1 egg, beaten
1 1/2 cups flour
1 cup whole wheat flour
1 tsp baking soda
1 tsp salt

For frosting:
1/4 cup butter
3/4 cup sugar
2 tsp cornstarch
1/4 cup buttermilk,
2/3 c. pecan halves, toasted then chopped

Preheat oven to 350 degrees. Grease and flour a 10X13 baking dish.
Combine the butter, sugar and molasses in a bowl. Beat until fluffy.
Add the eggs, vanilla and buttermilk and beat until combined.
Add the flours, baking soda and salt and mix until just combined.
Pour the cake batter into the prepared pan and bake at 350 for 45 minutes to an hour, or until a cake tester inserted in the center comes out clean.
While the cake is cooling, melt the 1/4 c. butter in a small saucepan, and cook until a deep nutty brown color.
Add sugar, cornstarch and buttermilk, and cook over high heat, 2-3 minutes. Let cool to warm.
Pour the icing over the cake, and sprinkle with pecans.