Preheat your oven to 350°F (175°C) and line an 8x8-inch baking dish with parchment paper. In a food processor, combine all-purpose flour, powdered sugar, and salt until well mixed. Add cold butter and pulse until the mixture resembles fine sand. In a separate bowl, whisk together the egg yolk, heavy cream, and vanilla, then gradually mix into the flour mixture until crumbly. Press the mixture into the lined pan, prick with a fork, freeze for 30 minutes, and then bake for 35 minutes or until slightly golden.

While the crust is cooling, bloom the unflavored gelatin in cold water as per package instructions. In a double boiler over simmering water, combine softened butter and granulated sugar, whisking until melted and blended. Then, add the egg yolks and mango puree, stirring constantly for about 15-25 minutes until the mixture thickens and coats the back of a spoon. Once thickened, melt the gelatin in a microwave for just a few seconds until liquid, mix it into the curd, and strain through a fine mesh sieve for a smooth texture.

Pour the silky mango curd over your cooled buttery shortbread crust, ensuring it's evenly spread. Warm the raspberry jam slightly in the microwave until pourable, then drizzle it across the mango filling. Use a skewer or knife to gently swirl the jam into the curd, creating a beautiful marbled effect. Refrigerate the assembled Raspberry Mango Bars for at least 4-6 hours or overnight, until the curd is fully set and firm.

To slice your Raspberry Mango Bars, run a warm knife around the edges of the dish to loosen any sticking. Cut into squares or rectangles for serving, ensuring clean edges.