In a pot boil cubed sweet potato, until soft and tender. Remove from heat and drain.
In a bowl lightly mash sweet potato and banana, until fully combined. Add egg and mix well. Add lentils, mix until fully combined, then add cinnamon.
In a skillet, add sweet potato mixture, blueberries and strawberries. Par cook breaking into pieces, remove from heat and place in a greased baking dish.
Bake at 350 degrees for 20-25 minutes, until golden brown.
For Vanilla Sauce: In a pot, add milk, brown sugar, butter, egg, flour, cinnamon and salt, whisk until smooth. Cook on medium heat, whisking constantly, until sauce has thickened. Stir in Vanilla until fully combined and remove from heat.
Pour vanilla sauce over warm crumble top with more berries and ready to serve.