Puree two of the mangoes in a food processor until completely smooth.
Combine the mango puree with a splash of water or orange juice to adjust consistency to a thin syrup.
Dice the remaining mango into small cubes for topping.
In a large bowl, whip cold mascarpone, heavy cream, powdered sugar, and vanilla extract on high speed until stiff peaks form.
Dip ladyfingers quickly into the mango nectar mixture and arrange a layer in a serving dish.
Spread a generous layer of the mascarpone cream over the ladyfingers.
Repeat layers until ingredients are used up, ending with a layer of cream.
Top with diced fresh mango cubes.
Chill the dessert for at least 6 hours before serving.