Preheat oven to 350 F.

In blender container, place egg, milk, bananas, and vanilla and blend until smooth. In large bowl, stir together oat flour, almond flour, cinnamon, baking powder, baking soda, and salt. Stir banana mixture into flour mixture. Fold in walnuts.

Grease 8 or 9 inch round cake pan and pour in batter. Bake in preheated oven for 25 minutes, or until a toothpick inserted into center of pie comes out nearly clean. Let cool for about 5 minutes before unmolding. In small saucepan, place 1/3 cup water, blueberries, maple syrup or honey, lemon zest, and a pinch of salt. Bring to a boil, reduce heat to medium-low, and simmer for 5 minutes. In small bowl, stir cornstarch or arrowroot powder into 1 Tbsp water until dissolved. Pour into blueberry mixture and stir. Simmer for another 3 minutes, or until mixture thickens.

Serve warm wedges of pancake pie with blueberry sauce and fresh basil leaves, if desired.