Preheat oven to 350 degrees F. Grease a 9x13-inch baking pan.

In a large bowl, whisk together the flour, sugar, baking soda, and salt.

Add the eggs, vanilla extract, and the entire can of crushed pineapple with its juice. Stir with a spoon until everything is just combined.

Pour the batter into the prepared pan and bake for 30 to 35 minutes, until a toothpick inserted in the center comes out clean.

While the cake bakes, make the frosting. In a medium saucepan over medium heat, combine the butter, sugar, and evaporated milk. Bring to a boil, stirring constantly, and cook for about 5 minutes until slightly thickened.

Remove from heat and stir in the shredded coconut, chopped pecans, and vanilla extract.

As soon as the cake comes out of the oven, poke holes all over the top with a wooden skewer or fork. Pour the hot frosting evenly over the hot cake.

Let the cake cool for at least 20 minutes before slicing and serving.