1. Preheat the oven to 325℉. Prepare a 9-inch springform pan with nonstick spray and parchment. Wrap with foil for a water bath. Set up a roasting pan in the oven and boil water for the bath.

2. In a bowl, beat cream cheese until smooth. Add sugar and salt, blend. Beat in eggs one at a time. Mix in sour cream, heavy cream, and vanilla. Pour into the prepared pan. Place into the roasting pan and add hot water to create a bath. Bake for 45 minutes. Cool on a rack, then freeze for 4–5 hours or overnight.

3. Preheat oven to 350℉. Prepare two 9-inch round cake pans with nonstick spray and parchment. Sift flour and salt in a bowl. In another bowl, beat oil and sugar for 2 minutes. Add eggs and vanilla, beat again.

4. Mix vinegar and baking soda in a small bowl, add to batter along with buttermilk and green food coloring. Beat until blended. Add dry ingredients and beat on medium-high for 2 more minutes. Divide into pans and bake for 30–35 minutes. Cool completely.

5. In a large bowl, beat cream cheese and butter until creamy. Mix in marshmallow creme. Add powdered sugar and beat until smooth and spreadable.

6. Place one cake layer on a serving plate. Remove frozen cheesecake from the pan and parchment, trimming to fit if needed. Place on top of the first cake layer. Add the second cake layer on top.

7. Apply a thin crumb coat of frosting. Chill for 30 minutes. Add a second layer of frosting, smoothing evenly over top and sides. Decorate as desired.