Preheat oven to 350 degrees F.  In a small bowl, mix flour, baking soda, baking powder, and salt.  Set aside.

In a medium bowl cream together sugar, oil, eggs, and vanilla.  Alternately add the dry ingredients and the buttermilk in three additions to the creamed mixture.  Gently stir in the bananas and nuts.

Pour the batter into a greased 9-by-5-inch loaf pan.  Bake for 45 to 55 minutes, or until a toothpick comes out clean. Let the bread cool in the pan for 5 minutes. Finish cooling on a wire rack.

Preheat the oven to 425°F.

Place the pie crust in a pie plate and pinch the edges to create a rim. Use a fork to prick holes in the dough. Fill the crust with pie weights or beans. Bake 15 minutes. Remove the pie weights. Reduce the oven temperature to 375°F and bake an additional 15 to 20 minutes, until golden brown. Let cool completely.

While the crust is cooling, in a medium saucepan over medium heat, combine the white sugar, cocoa, flour, and salt. Mix well. Whisk in the milk. Stir constantly with a wooden spoon while the mixture comes to a low boil and becomes thick, 5 to 7 minutes. Reduce the heat to very low. Stir a couple of tablespoons of the hot mixture into the egg yolks. Stir the egg yolks back into the hot milk mixture. Stir constantly until thickened, 3 to 4 minutes. Remove from the heat and stir in 1 teaspoon of the vanilla extract.

Line the crust with half of the banana slices. Pour the pudding into the pie crust. Top with the remaining banana slices. Cover with plastic wrap and refrigerate until chilled, about 2 hours.

Using an electric mixer on high speed, beat the cream, confectioners’ sugar, and remaining 1 teaspoon vanilla until stiff peaks form. Spread the whipped cream on the pie. Top with chocolate shavings. Refrigerate until serving time.