Preheat oven to 325°F (163°C). Grease a 9-inch springform pan, line the base with parchment paper, and wrap the outside tightly with aluminum foil.
Pulse Oreo cookies in a food processor until fine crumbs form. Mix with melted butter until moistened. Press firmly into the bottom and 1 inch up the sides of the prepared pan. Bake for 10 minutes, then cool on a wire rack while preparing filling.
Chop Snickers bars into 1/2-inch pieces. Reserve 3/4 cup for topping, and freeze the remaining 1 1/2 cups for 10 minutes before folding into the batter.
Beat softened cream cheese on medium speed for 2-3 minutes until smooth. Add brown sugar and flour, mixing until combined. Add sour cream and vanilla, mixing on low. Add eggs one at a time, mixing on low just until incorporated. Gently fold in the chilled Snickers pieces.
Pour filling over cooled crust and spread evenly. Tap the pan gently to release air bubbles. Bake at 325°F for 55-65 minutes, until edges are set and the center has a gentle wobble.
Turn off the oven and crack the door open 1 inch. Let the cheesecake rest inside for 1 hour. Remove, run a knife around the edges, and cool completely on a wire rack for 1-2 hours. Refrigerate for at least 6 hours or overnight.
Remove cheesecake from the refrigerator and unclasp the springform pan. Place chocolate chips in a heatproof bowl. Heat heavy cream until simmering, pour over chips, and let sit for 3 minutes. Stir until smooth, then let cool for 5 minutes.
Pour ganache over the top of the chilled cheesecake and spread to the edges, allowing it to drip down the sides. While still tacky, scatter chopped Snickers and optional peanuts over the top. Drizzle generously with salted caramel sauce.
Refrigerate for at least 30 minutes to set the ganache and toppings. Serve chilled, wiping the knife clean with a warm, damp cloth between each slice for clean cuts.