Prepare the Cake:

Preheat Oven:

Preheat your oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan or line it with parchment paper.

Mix the Batter:

In a large bowl, combine the yellow cake mix, vegetable oil, eggs, crushed pineapple with juice, and vanilla extract. Mix until well blended.

Bake:

Pour the batter into the prepared baking pan and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Allow the cake to cool completely in the pan.

Make the Filling:

Cook the Filling:

In a medium saucepan, combine the crushed pineapple, sugar, and shredded coconut. Cook over medium heat, stirring occasionally, until the mixture thickens slightly (about 5-7 minutes). Remove from heat and let it cool.

Assemble the Cake:

Using a fork, gently poke holes across the cooled cake. Spread the cooled pineapple coconut filling evenly over the top.

Prepare the Whipped Topping:

Whip the Cream:

In a chilled mixing bowl, beat the heavy whipping cream, powdered sugar, and vanilla extract until stiff peaks form.

Frost the Cake:

Spread the whipped topping evenly over the pineapple coconut filling.

Garnish:

Sprinkle toasted coconut on top for garnish.

Serve:

Chill and Serve:

Refrigerate the cake for at least 1 hour before serving to allow the flavors to meld.