For the Graham Cracker Crust:
2 cups graham cracker crumbs (about 14 full sheets)
2 tablespoons granulated sugar
½ cup (1 stick) unsalted butter, melted
For the Toasted Marshmallow Cheesecake Filling:
10 jumbo marshmallows
4 packages (8 oz each) cream cheese
1 cup granulated sugar
½ teaspoon kosher salt
4 large eggs, room temperature
½ cup sour cream, room temperature
¼ cup heavy cream
1 teaspoon vanilla extract
2 tablespoons cornstarch
For the Chocolate Ganache Topping:
½ cup heavy whipping cream
1 cup semi-sweet chocolate chips
Optional Garnishes:
Additional marshmallows (regular or jumbo)
Graham cracker squares
Milk chocolate bar pieces
Instructions
Preheat oven and prepare the crust
Set your oven to 350°F. In a medium bowl, stir together the graham cracker crumbs, 2 tablespoons of sugar, and melted butter until the mixture resembles wet sand and clumps together when squeezed in your fist. Press the mixture firmly into the bottom and about ½ inch up the sides of a 9-inch springform pan, using the flat bottom of a measuring cup to pack it tightly. Bake the crust for 10 minutes, then remove it from the oven and let it cool on the counter. Once the pan is cool enough to handle, wrap the bottom and sides tightly with two layers of heavy-duty aluminum foil. Set aside.
Toast the marshmallows
Lightly grease a small baking sheet with nonstick spray. Arrange the jumbo marshmallows in a single layer on the sheet, leaving a little space between each. Place the sheet in the 350°F oven for about 5 minutes, watching closely, until the marshmallows puff and turn golden brown on top. Remove from the oven and set aside.
Make the cheesecake batter
In a large mixing bowl, beat the softened cream cheese, 1 cup of granulated sugar, and kosher salt together with an electric hand mixer on high speed until the mixture is completely smooth, light, and fluffy (about 2 minutes). Scrape down the sides and bottom of the bowl with a rubber spatula.
Add eggs and dairy
Reduce mixer speed to medium. Add the eggs one at a time, beating well after each addition and scraping the bowl between each egg. After all eggs are incorporated, add the sour cream, heavy cream, and vanilla extract. Mix on medium speed just until smooth and uniform.
Fold in the toasted marshmallows
With the mixer on the lowest speed, gradually add the toasted marshmallows to the batter a few at a time. If the marshmallows climb up the beaters, stop the mixer and scrape them back down with a spatula. Mix only until the marshmallows are broken down and mostly incorporated—small lumps from the browned edges are fine and will melt during baking. Finally, add the cornstarch and mix on low just until combined.
Assemble the water bath and bake
Pour the cheesecake batter into the cooled crust and smooth the top. Place the foil-wrapped springform pan into a larger roasting pan or baking dish. Carefully pour boiling water into the outer pan until it reaches about halfway up the sides of the springform pan. Transfer the entire setup to the oven. Bake for 1 hour and 15 minutes. After 45 minutes, check the top; if it is already golden brown, loosely lay a sheet of aluminum foil over the cheesecake (do not press it onto the surface) to prevent over-browning.
Cool slowly in the oven
Turn off the oven and prop the door open about 1–2 inches using a wooden spoon handle. Allow the cheesecake to cool inside the oven for 1 hour. This gradual cooling prevents cracking. After 1 hour, remove the cheesecake from the oven and lift the springform pan out of the water bath. Unwrap the foil from the sides. Let the cheesecake cool on the counter for 30 minutes. Then cover the pan with plastic wrap and refrigerate for at least 5–6 hours, or overnight.
Make the chocolate ganache
About 1 hour before serving, prepare the ganache. In a small saucepan, heat the ½ cup of heavy cream over medium heat until it is steaming and small bubbles form around the edge (do not boil). Place the semi-sweet chocolate chips in a heatproof bowl. Pour the hot cream over the chocolate and let it sit for 1 minute. Whisk gently until the chocolate is completely melted and the mixture is smooth and glossy. Let the ganache cool for 5 minutes at room temperature until it thickens slightly.
Finish and serve
Remove the cheesecake from the refrigerator. Unlock and remove the outer ring of the springform pan. Pour the cooled ganache over the top of the cheesecake, using an offset spatula to spread it evenly to the edges. If desired, garnish with additional marshmallows, graham cracker squares, and broken chocolate bar pieces. Slice with a knife dipped in hot water (wiped clean between cuts) and serve chilled. Store leftovers in the refrigerator for up to 3 days, pressing a piece of wax paper against any cut surfaces to keep the cheesecake from drying out
