Preheat your oven to 350°F (175°C) and line an 8x8 inch baking dish with parchment paper. In a food processor, combine the all-purpose flour, powdered sugar, and salt. Blend until mixed, then add cold butter pieces, pulsing until the mixture resembles coarse sand. Whisk together the egg yolk, heavy cream, and vanilla, then add this to the dry ingredients to form a crumbly dough. Press the dough firmly into the prepared dish, prick it with a fork, chill for 30 minutes, and bake for 15 minutes with weights, followed by another 20 minutes until golden. Let it cool completely.

While the crust cools, begin preparing your mango curd. In a small bowl, bloom the unflavored gelatin powder in cold water for about 5 minutes. Set up a double boiler, and in it, combine softened butter and granulated sugar, whisking until creamy. Gradually add the egg yolks, mango puree, salt, and fresh lemon juice. Stir continuously for 15 to 25 minutes, or until the mixture thickens enough to coat the back of a spoon. Finally, mix in the bloomed gelatin until fully incorporated, ensuring a smooth texture, then pour the curd over the cooled crust.

To create a beautiful swirl on your Raspberry Mango Bars, gently warm the raspberry jam in a microwave for about 10 seconds. Drop spoonfuls of the jam over the mango curd and use a knife to swirl it lightly, creating a marbled effect. Aim for a balance of visible mango curd and raspberry for a striking appearance. Once swirled, refrigerate the bars for at least 4 to 6 hours or until fully set, allowing the flavors to meld perfectly.

Once set, carefully lift the bars out of the baking dish using the parchment paper overhang. Place on a cutting board and slice into squares, wiping the knife with a damp cloth between cuts for clean slices. Serve these delightful Raspberry Mango Bars chilled, showcasing their bright colors and creamy texture.