01 - Combine diced mangoes, lime juice, and sugar in a blender. Process until completely smooth. Transfer to a bowl and set aside.
02 - In a large mixing bowl, combine mascarpone cheese, powdered sugar, and vanilla extract. Using an electric mixer, beat on medium speed until the mixture is smooth and creamy, approximately 2 minutes.
03 - In a separate chilled bowl, whip the heavy cream using an electric mixer or whisk until stiff peaks form. The cream should hold its shape when the whisk is lifted.
04 - Gently fold the whipped cream into the mascarpone mixture using a spatula. Incorporate with light, folding motions until fully combined and fluffy. Avoid overmixing to maintain airiness.
05 - In a shallow dish wide enough to accommodate ladyfingers, combine the cooled coffee with rum or mango juice. Stir gently to mix.
06 - Quickly dip each ladyfinger into the coffee mixture for 1-2 seconds per side—do not soak. Arrange dipped ladyfingers in a single layer at the bottom of an 8x8 inch serving dish or individual serving glasses.
07 - Spread half of the mango puree evenly over the ladyfingers. Top with half of the mascarpone cream, spreading smoothly with a spatula to create an even layer.
08 - Repeat the layering process: dip remaining ladyfingers, arrange them as the second layer, top with remaining mango puree, and finish with remaining mascarpone cream. Smooth the top surface.
09 - Cover the dish tightly with plastic wrap, ensuring it touches the surface to prevent skin formation. Refrigerate for at least 4 hours; preferably overnight for optimal texture and flavor development.
10 - Just before serving, decorate the top with thinly sliced fresh mango arranged in a decorative pattern. Garnish with fresh mint leaves for color contrast. Serve chilled.