Step 1 — Make the Crust : Preheat oven to 350°F (175°C). Mix graham crumbs, sugar, and salt. Stir in melted butter until evenly coated. Press into a 9-inch tart pan (bottom + sides). Bake for 8–10 minutes, then cool completely.

Step 2 — Prepare the Ganache Filling : Heat heavy cream until steaming (not boiling). Pour over chopped chocolate in bowl. Let sit 2 minutes, then stir smooth. Add butter + vanilla and mix until glossy. Pour into crust and refrigerate 1–2 hours to set.

Step 3 — Marshmallow Topping : Choose one of two options: A. Quick Option — Mini Marshmallows Top chilled tart entirely with marshmallows. Toast under the broiler 30–90 seconds until browned (watch very closely!) B. Homemade Marshmallow Fluff ,Beat egg whites + cream of tartar until soft peaks. Add sugar gradually until glossy stiff peaks form. Mix in vanilla. Spread over tart and torch for toasted effect.

Step 4 — Chill u0026 Serve : Chill 15 minutes after toasting to hold structure.