Step 1: Preheat and Prep the Pans
Let’s get rolling—crank your oven to 300°F and feel the kitchen buzz with promise. Grab three 8-inch cake pans—grease the sides with butter or spray, then line the bottoms with parchment circles (I love that extra slip!). Take a sec to breathe—this is gonna be a s’mores wonder, and you’re already on your way.

Step 2: Whisk the Dry Mix
In a big bowl, whisk 2 cups flour, 2 cups sugar, 3/4 cup cocoa powder, 2 tsp baking soda, and 1 tsp salt—give it a good stir (I love that cocoa cloud poofing up!). It’s all dry and ready—set it aside and feel the chocolate vibes starting. This is the base of our fudgy dream!

Step 3: Blend the Wet Magic
In another bowl, mix 2 large eggs, 1 cup milk, 1 cup vegetable oil, and 1 1/2 tsp vanilla—whisk ‘til smooth (I grin every time it blends!). Heat 1 cup water ‘til boiling, add it in, and mix ‘til it’s a thin, velvety batter—don’t worry about the runny look (my heart’s racing with that hot water trick!). This is where the moistness comes alive!

Step 4: Bake the Layers
Divide the batter evenly between your three pans—smooth the tops and pop them in the oven for 30-33 minutes—check with a toothpick ‘til it’s got a few crumbs (I love watching them puff up!). Cool in the pans for 5 minutes, then turn onto racks to cool completely—I’m drooling just thinking about it! Let them chill while you prep the rest.

Step 5: Make the Graham Crunchies
Crank the oven to 350°F—line a cookie sheet with parchment or a silicone mat (I love that non-stick ease!). Mix 3/4 cups graham cracker crumbs, 1 1/2 tbsp sugar, and 1/4 cup melted unsalted butter—stir ‘til it’s a sandy mix (that buttery smell gets me every time!). Spread it on the sheet, bake 8-10 minutes ‘til golden, then cool—set aside that crispy goodness.

Step 6: Toast and Whip the Frosting
Spread 1 1/2 cups mini marshmallows on a tray—toast under the broiler for 1 minute ‘til golden and smoky (I watch like a hawk so they don’t burn!). Cool completely—beat 1 3/4 cups unsalted butter in a big bowl ‘til smooth, add 3 1/4 cups marshmallow fluff, then 6 cups powdered sugar in halves, mixing ‘til fluffy (I love that gooey swirl!). Break up the cooled marshmallows and mix them in—set aside this s’mores heaven!

Step 7: Melt the Ganache
Toss 9 oz semi-sweet chocolate chips in a bowl—heat 3/4 cup heavy whipping cream ‘til it simmers, pour over the chips, and let sit 3-5 minutes (I love that steamy wait!). Whisk ‘til smooth—set aside to cool ‘til thick but pourable (I test it later—it’s ganache time!).

Step 8: Whip the Vanilla Frosting
Beat 3/4 cup unsalted butter ‘til smooth—add 3 cups powdered sugar in halves, 1 tsp vanilla, and 1 tbsp milk or cream, mixing ‘til creamy (I love that silky dam builder!). Set aside—it’s ready to hold everything in place.

Step 9: Build the Cake
Level the cake tops with a serrated knife—place one layer on a stand, pipe a vanilla frosting dam around the edge (I feel pro doing this!). Spread 6 tbsp ganache inside, top with 1 cup marshmallow frosting, then 1/2 cup graham crunchies—stack the second layer, repeat, and top with the third (I chill it 30 minutes to set—patience pays off!).

Step 10: Frost and Drip
Frost the outside with the rest of the marshmallow frosting—keep it thick on top for that naked look (I smooth it with glee!). Press leftover crunchies into the bottom—reheat the ganache if needed, pour over the top, and drip down the sides with a bottle (I go slow and feel fancy!). Toast extra mini marshmallows with a torch and pile on top—slice and serve cool for that s’mores kick!