Preheat the oven to 350°F. Grease two 8-inch round cake pans and line the bottoms with parchment paper.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt and cardamom. Set aside.
In a large bowl, whisk the mango puree, yogurt, lemon juice and sugar until smooth. Whisk in the oil, melted butter and vanilla.
Add the dry ingredients to the wet mixture and fold gently just until combined. Divide the batter evenly between the pans and smooth the tops.
Bake for 28-32 minutes, until golden and a toothpick inserted in the center comes out clean. Cool in the pans for 10 minutes, then transfer to a wire rack and cool completely.
For the mango cream, beat the mascarpone and powdered sugar until smooth. Add the cold heavy cream and beat until stiff peaks form, then gently fold in the chilled mango puree.
Place one cake layer on a plate, spread with a thick layer of mango cream and scatter 1 cup of diced mango over it. Top with the second layer and frost the top and sides with the remaining cream.Pile the rest of the diced mango on top and chill for 1 hour before slicing.