Preheat oven to 400°. Line a large baking sheet with parchment paper; set aside.

Zest peel from 1 Cara Cara orange, blood orange, grapefruit, and lemon; set each separately aside. Cut to remove remaining peel and pith from each citrus. Thinly slice the fruit; remove seeds and set fruit aside.

For syrup, juice remaining Cara Cara orange. Combine juice and ½ cup sugar in small saucepan. Cook over medium heat for 11 to 15 minutes or until reduced by half. Remove from heat and stir in 1 teaspoon each reserved Cara Cara orange, blood orange, grapefruit, and lemon zests.

Roll out puff pastry on a lightly floured surface to a 13×9-inch rectangle. Transfer to prepared baking sheet. Lightly brush top of puff pastry with ⅓ of Cara Cara syrup.

Bake puff pastry for 12 to 15 minutes or until the edges are golden brown. Remove from oven and lightly brush with ⅓ Cara Cara syrup. Cool on baking sheet for 10 minutes. transfer pastry to serving tray.

Stir together mascarpone and cream cheese, remaining 2 tablespoons sugar, and 1 teaspoon each reserved Cara Cara orange, blood orange, grapefruit, and lemon.