Coat a loaf pan with a light film of fat and flour.
Puree the bananas and lemon juice.
Sift together the flour, baking powder, baking soda, and salt.
Combine the sugar, banana purée, eggs, and oil in with an electric mixer, mix on medium speed with the paddle until blended. Scrape the bowl as needed.
Add the sifted dry ingredients and mix just until combined. Mix in the crushed Barras de Coco. Pour batter into the loaf pan and top with shredded coconut.
Bake at 350 °F until the bread springs back when pressed and a tester inserted near the center comes out clean, about 55 minutes.
Cool the loaves in the pans for a few minutes, then unmold and transfer them to wire racks and cool completely.