Preheat your oven to 350°F (175°C). Grease a 9x5 inch loaf pan and line with parchment paper, allowing some overhang for easy removal.
In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt until well combined.
In a separate medium bowl, beat the eggs until frothy, then add oil, vanilla extract, and the 2 tablespoons of reserved pineapple juice. Whisk until well combined and slightly thickened.
Place your crushed pineapple in a fine mesh strainer and press firmly to remove excess moisture.
Pour the wet ingredients into the dry ingredients, stirring just until moistened. Fold in the drained pineapple and nuts (if using), being careful not to overmix.
Pour the batter into your prepared loaf pan, smoothing the top with a spatula. Bake for 55-60 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Allow the bread to cool in the pan for 15 minutes before transferring to a wire rack. For the cleanest slices, wait at least 1 hour before cutting.