Fill a large roasting pan about one-third of the way with water and carefully place on the middle oven rack. Preheat the oven to 325 degrees F. Wrap the outside of an 8-inch springform pan with aluminum foil. Coat the inside of the pan with cooking spray.
Finely crush 3 chocolate cookies and sprinkle the crumbs in the bottom of the springform pan; tap out the excess. Beat the cream cheese in a large bowl with a mixer on medium-high speed until light and fluffy, about 3 minutes. Add the sugar, eggs, 3/4 cup cream and the vanilla. Reduce the mixer speed to medium and beat until the sugar is dissolved and the mixture is creamy, scraping down the bowl as needed (do not overbeat; if there are still lumps, whisk the batter by hand to smooth them out).
Put the chocolate and the remaining 1/4 cup cream in a microwave-safe bowl and microwave until the chocolate melts, about 45 seconds. Stir in the cocoa powder until smooth.
Divide the batter between 2 large liquid measuring cups or bowls (about 2 1/2 cups batter in each). Stir the melted chocolate mixture into one of the batters. Pour about half of the vanilla batter into the pan, then slowly pour half of the chocolate batter into the center of the vanilla, letting it spread. Pour the remaining vanilla batter into the center of the chocolate batter, letting it spread; pour the remaining chocolate batter into the middle.
Carefully transfer the cheesecake to the pan of hot water and bake until the edges are set but the center still jiggles slightly, 1 hour, 30 minutes to 1 hour, 45 minutes. Turn off the oven and keep the cheesecake in the oven with the door ajar, 30 minutes. Remove the cheesecake from the water bath and transfer to a rack. Run a knife around the edge of the cake to loosen and let cool completely, then refrigerate overnight.
Remove the springform ring. Crush the remaining 3 chocolate cookies and toss in a bowl with the crushed meringues and peanuts. Press into the sides of the cake.
To get clean cuts, dip your knife in hot water and wipe dry between slices.