2 tablespoons raspberry mixture (left over from filling)
For the Crust:
Preheat the oven to 375°F.
Place graham crackers, sugar, and salt in a food processor and pulse until fine crumbs form. With the machine running, slowly stream in the melted butter. The mixture should be moist and clumped in spots. If it looks too dry, add 1 tablespoon of water at a time, pulsing to combine.
Press the mixture into a greased tart or pie pan, evenly distributing the mixture on the bottom and up the sides. Bake for 8-10 minutes or until lightly golden. Allow to cool completely.
For the Filling:
Wipe out the food processor and add the raspberries and the sugar.
Puree until completely smooth. Pour the mixture through a fine-mesh strainer and discard the pulp.
Place the chopped chocolate in a heat-safe bowl. Heat the cream in a small saucepan until barely simmering.
Pour the hot cream over the chocolate and stir until completely melted.
Stir in the salt, vanilla, and ⅓ cup of the raspberry mixture.
Pour into the prepared crust, cover with plastic wrap, the refrigerate for at least 6 hours.
For the Topping:
When the filling is set, add a small amount of water to a small saucepan and bring to a simmer.
Put the egg whites, sugar, cream of tartar, and salt in a heat-safe bowl (I use the bowl from my stand mixer) and whisk to combine.
Place the bowl in the saucepan (making sure the bottom of the bowl doesn’t touch the simmering water) and whisk constantly for 5-7 minutes or until the sugar is dissolved and the mixture is hot to the touch.
Transfer the bowl to the stand mixer fitted with the whisk attachment and mix on medium speed for a minute or so.
Add the raspberry mixture and vanilla. Increase the speed and whip the mixture until stiff, glossy peaks form, about 15 minutes.
Spread the mixture over the tart filling, occasionally lifting your spoon or spatula to create little decorative peaks.
Using a kitchen torch, lightly brown the peaks (I did a little bit more than just the peaks because I LOVE the flavor of toasted marshmallows). Alternatively, you can place the entire tart until the broiler for about 30-45 seconds, watching it carefully the entire time. Slice the tart and serve.