Preheat your oven to 350°F (175°C). Grease and flour a 9×5 inch loaf pan, or line with parchment paper for easy removal.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt until well combined.
In a separate bowl, beat the eggs lightly, then add oil, vanilla extract, and the 2 tablespoons reserved pineapple juice. Whisk until smooth and well combined.
Pour the wet mixture into the dry ingredients and stir just until combined. Don't overmix - aim for no more than 15-20 strokes with your spoon or spatula.
Gently fold in the drained crushed pineapple. If using, add the chopped nuts and shredded coconut now. Make sure the pineapple is evenly distributed throughout the batter.
Pour the batter into your prepared loaf pan and smooth the top. Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center comes out clean. If the top browns too quickly, loosely cover with aluminum foil after about 40 minutes.
Allow the bread to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.