Preheat your waffle iron according to manufacturer instructions, allowing it to heat for at least 5 minutes for best results.
In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt until evenly combined.
In a separate bowl, whisk together the buttermilk, eggs, melted butter, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients and stir gently until just combined with a few small lumps remaining. Do not overmix.
Fold in the drained pineapple, toasted coconut, and chopped macadamia nuts until evenly distributed throughout the batter.
Lightly grease the waffle iron with cooking spray or a small amount of melted butter. Pour the recommended amount of batter onto the center of the iron (usually about 1/2 to 3/4 cup depending on your iron size).
Close the lid and cook according to your waffle iron's timing, typically 3-5 minutes, until the waffles are golden brown and crisp on the outside.
Remove the waffle carefully with a fork or silicone tongs and keep warm in a 200°F oven while you cook the remaining batter. Serve immediately with your favorite toppings.
