S’more Pie…adapted from Gourmet
1 1/2 graham cracker crumbs (from about 10 whole graham crackers)
Special equipment: a candy thermometer
Put oven rack in middle position and preheat oven to 350°. Stir together all ingredients in a bowl and press evenly on bottom and up side of 9 inch pie plate. Bake until crisp, about 12 minutes, then cool on a rack to room temperature, about 45 minutes.
Reheat oven 350°F. Gently microwave cream till almost boiling. Add chopped chocolate and let stand about a minute. Whisk until chocolate is melted and mixture is smooth. Gently whisk in egg and a pinch of salt until combined and pour into graham cracker crumb crust (crust will be about half full).
Cover edge of pie with a pie foil (I forgot this step so my crust is a little dark), and bake until filling is softly set and wiggles slightly in the center when gently shaken, about 25 minutes. Cool pie to room temperature on a rack (filling will firm as it cools), about 1 hour.
Sprinkle gelatin over 1/4 cup cold water in a large deep heatproof bowl and let stand until softened, about 1 minute.
Stir together sugar, corn syrup, a pinch of salt, and remaining 1/4 cup water a large, heavy saucepan. Bring to a boil over moderate heat, stirring until sugar is dissolved, then boil until thermometer registers 260°F, about 6 minutes.
Begin beating water and gelatin mixture with an electric mixer at medium speed, then carefully pour in hot syrup in a slow stream, beating (avoid beaters and side of bowl). When all of syrup is added, increase speed to high and continue beating until mixture is tripled in volume and very thick, about 5 minutes. Add vanilla and beat until combined. Immediately spoon topping onto center of pie filling; it will slowly spread to cover top of pie. Chill, uncovered, 1 hour, then cover loosely with lightly oiled plastic wrap, and chill 3 hours more. May prepare up to this step one day before serving.
Before serving, preheat broiler. Place pie on a baking sheet. Cover edge of pie with foil and broil 3 to 4 inches from heat, rotating pie as necessary, until marshmallow topping is golden brown, about 3 minutes. Cool pie on a rack 10 minutes. Slice pie with a large heavy knife dipped in hot water and then dried with a towel before cutting each slice.