Chocolate S'Mores Tart with Toasted Marshmallow

Shortcrust Pastry
1 Line a 9-inch (22 cm) tart ring or a fluted tart pan with removable bottom with shortcrust pastry dough. Fully blind bake the crust according to directions in the pastry recipe. Let the tart shell cool completely. 
Chocolate Ganache Filling
4 Place chopped chocolate in a medium mixing bowl.
3 Whisk together heavy cream, espresso powder, water and vanilla in a medium saucepan. Bring to a simmer on medium heat. 
5 Pour the warm cream mixture over the chopped chocolate and stir with a spatula until the chocolate has completely melted. Stir in the softened butter until you have a smooth glossy liquid ganache. 
19 If the chocolate doesn't completely melt, warm slightly and stir again. 
Fill the Pastry Shell
7 Place the empty tart shell on a serving plate. Pour the warm ganache directly into the tart shell, filling almost to the edge of the crust. Place in the fridge for about 30-40 minutes until the chocolate has set. Remove from the fridge and keep at room temp for adding the meringue.
Swiss Meringue
10 Place a medium saucepan filled with 1-inch of water on medium heat. 
9 In the metal bowl of a stand mixer, combine the egg whites and granulated sugar. Immediately whisk by hand to create a foamy liquid.
11 Set the mixing bowl on top of the saucepan to create a double broiler. 
12 Whisk the egg whites and sugar continuously until the temperature on an instant thermometer reads 160°F (72°C). Carefully dip your finger into the hot sugar and rub the mixture between your fingertips. If you don't feel any grains of sugar, the mixture is ready. (about 6-8 minutes)
13 Remove the mixing bowl from the heat and wipe the bottom of the bowl dry with a towel. Place the bowl on the mixing stand fitted with the whisk attachment and begin whipping on high speed.
14 Continue to whip until a thick, glossy and marshmallow like meringue with stiff peaks is formed. Stiff peaks means the meringue will hold its shape and not sing back over on itself. Lift the whisk from the bowl and if the meringue is thick and creates a "peak" or point without slumping it's good to go. The bowl should be cool or at least room temperature to the touch. (about 8-10 minutes)
Assemble
16 Dollup the meringue on top of the set chocolate filling. I use a spoon to create whips with the meringue. 
17 Carefully toast the meringue with a kitchen torch on a low setting. Keep the torch moving to prevent over browning the meringue. 
18 Slice and serve at room temperature.