Start by preheating your oven to 350°F (175°C). In a mixing bowl, combine the graham cracker crumbs, unsalted butter, corn syrup, and a pinch of sea salt. Mix until the crumbs are evenly coated and the mixture resembles wet sand.
Press the crumb mixture into the bottom and up the sides of a 9-inch tart pan. Make sure the crust is packed tightly and evenly. Bake in the preheated oven for 8-10 minutes, or until golden and slightly firm. Remove from the oven and let it cool completely.
In a heatproof bowl set over a simmering pot of water (or using a microwave), melt the dark and milk chocolate until smooth. Stir in the heavy whipping cream and 1 tablespoon of unsalted butter, mixing until well combined and glossy.
Spread the raspberry jam evenly over the cooled crust. Pour the melted chocolate mixture over the jam, spreading it evenly to cover the jam completely. Set aside to cool slightly.
In a clean mixing bowl, beat the egg whites with a hand mixer until soft peaks form. Gradually add the granulated sugar while continuing to beat until stiff peaks form. Add the cream of tartar and vanilla, beating until fully incorporated.
Carefully fold in the finely ground freeze-dried raspberry powder into the meringue until just combined. Be gentle to keep the mixture light and airy.
Spoon the raspberry meringue over the chocolate filling, spreading it out to cover the surface completely. Create peaks and swirls for a beautiful finish.
Return the tart to the oven and bake for an additional 10-12 minutes, or until the meringue is lightly browned. Watch closely to prevent burning. Once done, remove from the oven and allow it to cool completely at room temperature.
Once cooled, garnish with fresh raspberries if desired. Slice, serve, and enjoy your Chocolate Raspberry Smores Tart with friends and family!