For the banana bread: Preheat the oven to 350 degrees F. Grease two 9-by-5-inch loaf pans with cooking spray.
With an electric mixer, cream the butter and sugar together until light and fluffy. Add the eggs one at a time, beating well after each addition. Beat in the bananas and vanilla. Sift the flour together with the baking soda and salt. Add the flour and buttermilk to the banana mixture, working in stages, and beginning and ending with the flour. Fold in the pecans.
Pour the batter into the prepared loaf pans and bake for 55 minutes. Cool slightly in the pan before turning the loaves out onto wire racks to cool completely.
For the chocolate chip sauce: Add the chocolate chips to a heat-proof bowl. Heat the heavy cream in a small saucepan until hot but not boiling. Pour the hot cream over the chocolate and stir until chocolate is fully melted. Serve over slices of banana bread.
Adapted from "Georgia Cooking in an Oklahoma Kitchen" by Trisha Yearwood (c) Clarkson Potter 2008. Provided courtesy of Trisha Yearwood. All rights reserved.