Preheat oven to 350 degrees F.
Butter 8 1/2 x 4 1/2 inch loaf pan. Dust pan with flour. Whisk eggs and oil together. In a separate bowl whisk together flour, sugar, baking powder, baking soda, spices and salt. Stir in brown sugar. Pour the wet ingredients over the dry. Mix until well combined - batter will be really thick, more like dough than batter. Stir in the mango and zest. Scrape the batter into the pan, and smooth the top. Bake the bread for 1 1/2 hours, or until it's golden brown on top and a knife comes out clean. Let cool for at least 5 minutes before removing it from the pan. Enjoy!