Preheat the oven to 350F degrees. Spray a 9x13-inch baking dish with nonstick cooking spray.
In a large bowl with an electric hand mixer (or the bowl of a stand mixer) add 1 box Duncan Hines French vanilla cake mix, 3 large eggs, room temperature, 1 cup whole milk, ⅓ cup unsalted butter, melted, and 2 Tablespoons sour cream. Mix for 2 minutes until combined well. Pour the batter into the prepared baking dish.
Bake the cake for 25-30 minutes or until the cake springs back under your finger and/or a toothpick inserted into the center comes out clean. Allow the cake to cool for about 5 minutes.
Make large holes in rows across the cake. A wooden spoon handle works well for this. You want them large enough so the pudding can go into them.
In a bowl whisk together 2 (3.4 ounce) boxes banana cream instant pudding, 3 cups cold whole milk and and one cup of the crushed pineapple with juice until combined and slightly thickened.
Pour the prepared pudding into the holes. Lightly pressing down with a spatula to ensure they are fully filled.
Evenly spread the remaining pudding mixture across the top of the cake.
Drain the remaining crushed pineapple and spread it on top of the pudding layer.
Cover loosely with plastic wrap and refrigerate for 3-4 hours or overnight. Poke cakes are better when they’ve had time to sit.
Serve slices with optional garnishes: fresh pineapple, toasted coconut.
Notes
Please refer to my FAQ’s (Frequently Asked Questions) and ingredient list above for other substitutions or for the answers to the most common questions.
If you aren't a fan of banana flavors, you could certainly use Coconut Cream Instant Pudding if you prefer that more. Also, you could use a Coconut Cake mix as well. Lots of ways to change up this cake to suit your tastes.