Preheat oven to 350 ℉ and grease a 9x13" pan and check the back of the box for cooking time on a 9x13".
Place the cake mix, pudding, sour cream, oil, eggs and milk in a bowl and mix to combine.
1 Box Red Velvet Cake Mix, 3.4 ounce Instant Red Velvet Pudding, 1 Cup Sour Cream, 1 Cup Canola Oil, 4 Eggs, ½ Cup Whole Milk
Pour into a cake pan and add about 10 minutes onto the back of the box cooking time.
Remove the cake from the oven, allowing it to cool for about 5 minutes, and then using the blunt end of a wooden spoon, poke holes over the cake.
Slowly pour the sweetened condensed milk mixture over the holes.
14 ounces Sweetened Condensed Milk
Place cake in fridge to cool for at least 10 minutes while you make the frosting.
Frosting
To the bowl of a stand mixer fitted with the paddle attachment, add the cream cheese, butter, confectioners’ sugar, vanilla and beat on medium-high speed until fluffy.
8 Ounces Whole Fat Cream Cheese, ¼ Cup Butter, 2 ½ Cups Powdered Sugar, ½ teaspoon Vanilla Extract
Spread the frosting into a smooth, even, flat layer using a spatula or knife. Refrigerate cake for at least 4 hours, or overnight. Before serving, cover in sprinkles or chocolate chips.