**Prepare the Mangoes**
In a mixing bowl, gently toss the mango chunks with a tablespoon of sugar (if using fresh mangoes) to enhance their sweetness. Let them sit for about 15 minutes to release some juices.
**Make the Pudding**
In a large mixing bowl, whisk together the instant vanilla pudding mix and cold milk for 2 minutes until smooth and thickened. Let it sit for 5 minutes to fully set.
**Layer the Trifle**
In the bottom of a trifle dish or individual serving glasses, place a layer of cubed cake or ladyfingers. Top with a layer of mango chunks, then spoon a layer of vanilla pudding over the mangoes.
**Add Whipped Cream**
Spread a layer of whipped topping over the pudding. If desired, sprinkle shredded coconut or toasted nuts over the whipped cream for added texture and flavor.
**Repeat the Layers**
Repeat the layers (cake, mangoes, pudding, whipped cream) until all ingredients are used, finishing with a generous layer of whipped topping on top.
**Garnish**
Decorate the top with fresh mango slices, a sprinkle of shredded coconut, toasted nuts, or a few mint leaves for an attractive finish.
**Chill and Serve**
Cover the trifle with plastic wrap and refrigerate for at least 2 hours, or overnight, to allow the flavors to meld together. Serve chilled.