In a bowl, sift the flour, cocoa powder, baking powder and salt and set a side.
In a large bowl, place the chopped chocolate and butter. Dissolve the instant coffee with the vanilla extract and pour it over the chocolate and butter.
Melt the butter and chocolate in the microwave using 30 seconds increments. Make sure the butter and chocolate have completely melted, before moving on.
Add the sugar to the melted chocolate and mix to combine.
Add the eggs and mix to combine.
Use a rubber spatula to gently fold the flour mixture into the chocolate mixture.
Gently pour the brownie mix on top of the par-baked graham crusts and bake for 20-22 minutes. The pies are ready when a toothpick comes out with just a few moist crumbs from the center of each pie. Immediately upon removing the pie from the oven, sprinkle the mini marshmallows. Turn your oven off and place the pies back in the oven with the door open to allow the mini marshmallow to melt.
Once cooled, and before serving, torch the mini marshmallows.