Preheat your oven to 350 °F (177 °C) and prepare a 9×13-inch cake pan by spraying generously with non-stick spray and set aside.
In a large mixing bowl, add the eggs, sour cream, milk, vegetable oil, and vanilla and whisk to combine.
3 eggs, ⅔ cup sour cream, ¾ cup milk, ⅓ cup vegetable oil, 1 teaspoon vanilla extract
Add in the cake mix and whisk until there are no dry spots remaining.
15.25 ounce box chocolate devils foods cake mix
Pour the batter into the prepared pan and tap on the counter a few times to remove any air bubbles.
Bake according to package instructions, approximately 25-30 minutes or until a toothpick inserted in the center comes out clean.
Allow the cake to cool for about 10 minutes on a wire rack then use the end of a wooden spoon (or whatever else you have readily available) to poke holes all over the cake.
Combine the pudding mix and milk into a small bowl and whisk until slightly thickened. Pour over the cake and make sure to get as much as possible in each of the holes.
3.5 ounce package chocolate pudding mix, 1 ½ cups milk
Spread the remaining evenly over the cake.
Refrigerate for at least 1 hour.
Once the pudding has set, top with chocolate fudge sauce. Spread evenly over the cake and refrigerate for 10-15 minutes.