Butter a 9-inch (23 cm) square pan or a loaf pan. Preheat the oven to 350F (180 C).
Sift together in a bowl the flours, baking powder, baking soda, salt, and cinnamon.
In a mixer, put in the bananas, jaggery, coconut water and yoghurt. Blend into a fine puree.
In a large bowl, place the melted ghee. Add the puree into this along with vanilla essence.
Make a well in the center of the flour mixture and stir in the wet ingredients with a spatula until almost mixed.
Add in the nuts and stir until just combined, but don''t overstir: stop when any traces of flour disappear.
Scrape the mixture into the prepared pan - top with banana slices nicely arranged, sprinkle sugar and cinnamon with some poppy seeds over the top and bake for 40 minutes, or until the center feels lightly-springy and just done.Cool on a wire rack.