Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius) and grease a 9x13 inch baking pan with butter or non-stick spray.

In a large mixing bowl, whisk together the eggs and melted butter until emulsified.

Incorporate the sweetened condensed milk, crushed pineapple with its juice, and vanilla extract into the egg mixture; stir until uniform.

In a separate bowl, sift together the all-purpose flour, baking powder, baking soda, and salt.

Gradually fold the dry ingredients into the wet pineapple mixture using a spatula until just combined, ensuring no flour pockets remain.

Pour the batter into the prepared baking pan and level the surface with an offset spatula.

Bake for 40 to 45 minutes in the center rack of the oven, or until a toothpick inserted into the center comes out clean.

Remove the pan from the oven and place on a wire rack to cool completely before slicing to allow the moisture to set.