Preheat the oven to 400 degrees F.
In the bowl of a food processor, add the flours, sugar and salt and pulse to combine. Drop in the cold butter and pulse until a coarse crumb texture forms. Add the vanilla and honey. Continue pulsing until the dough just comes together.
Press the dough into a 4 by 14-inch fluted tart pan or a 9-inch pie plate. Cover the crust with parchment paper or aluminum foil and weigh it down with either rice or pastry weights. Bake until lightly browned, about 15 minutes. If the crust is still pale in color, remove the parchment paper and pie weights and bake until lightly browned, about 5 minutes more. Let the pastry cool completely.
Melt the marshmallows in a heavy-bottomed saucepan over medium-low heat, stirring occasionally. Remove the pan from the heat when the marshmallows are thoroughly melted and smooth.
In a standing mixer fitted with the whisk attachment, whip the egg whites until soft peaks form. With the mixer running, pour in the melted marshmallows and whip until the ingredients are completely combined, smooth and slightly cooled. Spread the filling into the cooled crust. Refrigerate until the filling is completely set, about 30 minutes.
Heat the cream in a small pot over medium heat until hot. In a medium bowl, combine the chocolate with the butter. Pour in the hot cream and mix to melt the chocolate and incorporate the ingredients completely. Pour the glaze over the top of the marshmallow filling and spread it in an even layer so the filling is entirely covered. Return it to the refrigerator until the glaze sets up. Slice and serve.
Chefs NoteIf the dough still has a crumbly texture, add a tablespoon or 2 of cold water until it comes together.
Raw Egg WarningFood Network Kitchens suggest caution in consuming raw and lightly-cooked eggs due to the slight risk of Salmonella or other food-borne illness. To reduce this risk, we recommend you use only fresh, properly-refrigerated, clean, grade A or AA eggs with intact shells, and avoid contact between the yolks or whites and the shell.