Mix together in a bowl the flour, cornmeal, salt, cardamom, baking powder and baking soda.
In a larger bowl, place the mango puree, the sugar, the vanilla extract and oil. Using a hand mixer or whisk, whisk on medium speed about 2-3 minutes to dissolve the sugar into the puree.
Now whisk in the flour in three batches, beating no more than 20 seconds after each addition. Scrape the bottom and sides of the bowl with a spatula after every addition to ensure you have everything mixed in evenly.
Add the almonds and mix in with the spatula. Set the dough aside for five minutes. It will still be very sticky.
To shape the biscotti logs, get a bowl of water handy, and line a baking sheet with parchment paper.
Divide the batter into half and place the two mounds side by side on the baking sheet. Dunk your hands in the bowl of water to get them soaking wet, then shape each mound into a log, about 9 inches long by 3 inches wide. You want the top to be flat. There should be at least two inches of space between the two logs because they will expand in the oven.
Place the biscotti logs into a 325-degree preheated oven. Bake 37 minutes until firm and lightly browned.
Remove the logs and place them on a rack to cool, about five minutes. Now remove them to a chopping board and, using a serrated knife, cut each log diagonally into 3/4-inch thick slices. Be gentle because the logs are still not fully baked and you don't want them to crumble on you.
Place the slices, cut side down, on the baking sheeet. Return the baking sheet to the oven and bake another 25-30 minutes or until the biscotti are lightly brown.
Remove to a rack and cool thoroughly.