Preheat oven to 250°F. Set metal cooling rack over baking sheet. Set aside.
In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt. In another bowl, whisk together well shaken buttermilk, milk, eggs, and melted butter.
Slowly add wet ingredients to dry ingredients in three additions. Use a spatula to combine ingredients together. Mix until there are no longer any dry streaks of flour. Do not be alarmed if batter is a little lumpy.
Cover waffle batter with kitchen towel or plastic wrap and let sit for 5-8 minutes while you preheat waffle iron. Waffle iron temperature or setting will vary based on your machine.*
Once waffle iron is hot, lightly brushed the top and bottom with melted butter. Scoop batter size based of your waffle iron manufacturer's instructions. This will range from ⅓ cup for single waffle to 1 ¼ cup for a 4-set waffle.
Use a fork or tongs to gently transfer cooked waffles to prepared baking sheet. Keep in preheated oven for 5-10 minutes until waffles are crisp.*
Repeat with remaining batter. Serve waffles immediately.* Spoon slightly cooled ginger blueberry sauce over waffles and enjoy.