Preheat oven to 350°F (175°C). Coat a 9 x 13-inch (23 x 33 cm) baking pan with nonstick cooking spray.
cooking spray
Add chocolate cake mix, water, vegetable oil and eggs to a large mixing bowl. Mix according to package directions until well combined. Pour the chocolate cake batter evenly into the prepared pan.
1 (15.25 oz / 432 g) box Devil's Food chocolate cake mix, 1 cup (240 ml) water, ½ cup (120 ml) vegetable oil, 3 large eggs
Bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out clean.
While the cake is still hot, use the rounded handle of a wooden spoon to poke holes about 1/2 inch (1.3 cm) apart, stopping about three-quarters of the way through the cake rather than piercing the bottom. This keeps the pudding filling inside the cake instead of allowing it to collect underneath.
Prepare the pudding filling by adding the instant chocolate pudding mix to a medium bowl. Add the milk and whisk until smooth and beginning to thicken. Immediately pour the pudding over the hot cake before it sets, directing it into the holes and spreading it across the surface as needed.
1 (3 oz / 85 g) Snickers Milk Chocolate Instant Pudding Mix* , 2 cups (480 ml) whole milk
Drizzle 3/4 of the caramel topping over the pudding, then scatter 1/2 cup (73 g) of the roasted salted peanuts over the cake. Refrigerate for at least 1 hour, or until the cake is completely cooled and the pudding has set.
1 (12.25 oz / 347 g) jar caramel topping, 1 cup (146 g) roasted salted peanuts
Spread the thawed whipped topping evenly over the chilled cake. Drizzle with the remaining caramel topping, then finish with the remaining 1/2 cup (73 g) roasted salted peanuts and chopped Snickers bars. Keep refrigerated until ready to serve.
1 (8 oz / 227 g) container whipped topping , 3 full-size Snickers bars