Let’s whip up this cheerful Funfetti Birthday Poke Cake! It’s incredibly easy and fun. First, prepare and bake the cake base. Preheat your oven according to the temperature specified on your chosen vanilla cake mix package directions (usually 350°F/175°C). Generously grease a 9×13 inch cake pan.

In a large bowl, prepare the cake mix batter according to the specific instructions on the box, using the required amounts of eggs, oil, and water (or milk, if preferred). Once the batter is mixed and smooth, gently stir in the 1/4 cup of rainbow sprinkles until they are evenly distributed. Don’t overmix after adding sprinkles.

Pour the sprinkle-filled batter into the prepared 9×13 inch pan, spreading it evenly. Bake according to the package directions for a 9×13 pan, usually around 28-35 minutes. The cake is done when a wooden toothpick inserted into the center comes out clean.

Remove the baked cake from the oven and place the pan on a wire rack. Let the cake cool completely in the pan. This is very important; poking and filling a warm cake will result in a gummy mess. Cooling completely might take 1-2 hours.

Once the cake is fully cool, it’s time for the fun part – poking the holes! Using the rounded handle of a wooden spoon (or a similar tool like a thick straw or chopstick, about 1/2 inch wide), poke holes all over the top surface of the cake. Space the holes about 1-2 inches apart, pressing down almost, but not quite, to the bottom of the pan.

Now, prepare the pudding filling for the holes. In a medium bowl, combine ONE box of the vanilla instant pudding mix with 1 ½ cups of cold milk. Whisk together for about 1-2 minutes. You want the pudding to just begin to thicken but remain quite runny and pourable – thinner than regular pudding.

Carefully fill the holes with this runnier pudding mixture. You can use a small-tipped piping bag or Ziploc bag with the corner snipped to direct the pudding into the holes neatly. Alternatively, very carefully spoon the pudding over each hole, encouraging it to seep down. Once all holes are filled, pour any remaining runny pudding mixture evenly over the entire top surface of the cake and spread it thinly with a spatula.

Next, prepare the fluffy topping. In the same medium bowl (or a clean one), combine the SECOND box of vanilla instant pudding mix with the remaining 1 cup of cold milk. Whisk together for about 2 minutes until it becomes quite thick. Add the thawed frozen whipped topping to the thick pudding mixture. Gently fold the pudding and whipped topping together with a spatula until completely combined, light, and fluffy. Avoid vigorous stirring, which can deflate the topping.

Spread this fluffy pudding-whipped topping mixture evenly over the cake, covering the thin layer of pudding spread earlier. You can create gentle swirls with your spatula for texture. If you wish, reserve a small portion of the topping to pipe decorative swirls or borders later using a piping bag and star tip (optional).

Generously scatter extra rainbow sprinkles all over the top of the cake. Place the finished cake in the refrigerator and chill for at least 30 minutes (or preferably 1-2 hours) before serving. This allows the pudding in the holes and the topping to fully set. Slice into squares and serve chilled