IMPORTANT MEASURING NOTE – READ BEFORE BEGINNING: It’s very important to measure the flour correctly, using this method or a kitchen scale. (← That’s the one I own!) Too much flour will make your batter dry and your waffles bland.   IMPORTANT FLAVOR NOTE – READ BEFORE BEGINNING: I prefer to make my waffles on the not-very-sweet side (because I know how much syrup my family drizzles on theirs before eating!), so I intentionally add very little pure maple syrup to the batter.   If you'd prefer sweeter waffle batter, then substitute 2-4 tablespoons of pure maple syrup, honey, or agave for an equal amount of water. (For example, use 4 tablespoons + 2 teaspoons of pure maple syrup, and reduce the water to 2 tablespoons.)   IMPORTANT WAFFLE PAN NOTES – READ BEFORE BEGINNING: These are the waffle pans that I use. They’re really affordable and worth every penny! I baked waffles at least once a week for two months straight, and the pans still acted like they were as good as new!   Make sure to generously coat your waffle pans with cooking spray! The blueberries release juice as the waffles bake, and the juice can make the waffles stick more to the pans if you don’t spray them well.   If you'd like to use a traditional waffle maker, then see below for how to do so.   IMPORTANT BAKING NOTES – READ BEFORE BEGINNING: The blueberries will most likely poke up out of the batter after you’ve spread the batter into the waffle pans. That’s fine! The batter will rise up and completely engulf the blueberries after baking.   IMPORTANT STEP 4 NOTE – READ BEFORE BEGINNING: I do NOT recommend skipping Step 4. It makes a HUGE difference in the waffles’ texture! Without it, your waffles will be fluffy and tender, but they won’t have crispy outsides. You can easily toast leftover waffles straight from the refrigerator, too!   FLOUR ALTERNATIVES: Whole wheat pastry flour, regular whole wheat flour, or all-purpose flour may be substituted for the white whole wheat flour.   BUTTER + COCONUT OIL ALTERNATIVES: Any oil will work in place of the butter or coconut oil. Stick-style vegan butter will also work. (I like this one and this one.)   EGG WHITES NOTE + ALTERNATIVE: You must use both egg whites. The protein in the egg whites helps prevent your waffles from collapsing while cooling. If you didn’t use both egg whites, your waffles would sink some, and they'd also turn out denser and somewhat soggy in texture.   If you prefer to use whole eggs, then use 2 whole eggs AND decrease the milk by 1 tablespoon to compensate for the added volume from the yolks.   SWEETENER ALTERNATIVES: Honey or agave may be substituted for the pure maple syrup.   VINEGAR NOTES + ALTERNATIVES: Do not omit or substitute for the vinegar! It’s absolutely required. It reacts with the baking soda to make your waffles rise better and end up with a more tender texture. The vinegar flavor completely disappears after baking — I promise!   If you don’t have or can’t find distilled white vinegar, try to find another vinegar with a similar pH level of around 2.5 to maintain the same texture. Lemon juice has a pH level around 2-3, so it should also work.   MILK ALTERNATIVES: Any milk may be substituted for the nonfat milk.   FRESH BLUEBERRY NOTES + ALTERNATIVE: I prefer fresh blueberries because they taste a little juicier and don’t stain the waffle batter gray, like frozen ones do. In a pinch, you may substitute frozen blueberries, but your waffles may take an extra minute or two to bake.   GLUTEN-FREE OPTION: For the gluten-free flour, I recommend the following blend: 1 cup (120g) millet flour, ¾ cup (90g) tapioca flour, ½ cup (60g) brown rice flour, and 1 ½ teaspoons xanthan gum. Many store-bought gluten-free flour blends (I like this one from Bob's Red Mill) will also work, if measured like this.   TO MAKE USING A REGULAR WAFFLE IRON / WAFFLE MAKER: This recipe was specifically designed for baking. You can use the batter in a traditional waffle iron though! Just follow your waffle maker's instructions, and be sure to generously coat the waffle maker's plates with nonstick cooking spray before making each round of waffles.   Just remember… The "waffle maker" waffles will turn out more limp and soggy compared to the thick, firm, and fluffy baked waffles. If making the waffles in a regular waffle iron, do NOT skip Step 4 – it makes a HUGE difference in the waffles' final texture! Toasting your "waffle maker" waffles will give them the perfect firm and fluffy texture on the inside, as well as the classic lightly crisp outsides.   TO MAKE AS PANCAKES: Lightly coat a large pan or griddle with nonstick cooking spray, and preheat over low heat. Using 2 tablespoons of batter for each pancake, dollop onto the hot pan, and spread into a circular shape. Let the pancakes cook for 2-3 minutes, or until a slight skin starts to form around the edges and the bottom is light golden brown. Slide a spatula underneath, and flip. Continue to cook for another 1-2 minutes or until light golden brown on both sides. Serve hot. (See my blog post here for more cooking tips about how to make the best pancakes!)   HOW TO STORE: Store any leftover waffles in an airtight container in the refrigerator. They should keep for at least five days, if not longer!   HOW TO FREEZE: Line a baking sheet with foil (for easy clean-up!). Arrange the fully cooled waffles in a single layer on the foil. Place in the freezer for 2 hours or until fully frozen. Transfer to a zip-topped bag lined with a paper towel, and squeeze out as much air as you can before sealing the bag and placing it in the freezer.   No need to thaw them! Just pop these waffles into the toaster straight from the freezer, and cook them until they're warmed all the way through and crispy on the outside (like in Step 4).   HALVING THE RECIPE: This recipe is easily halved, if needed!   For more information, please read through the text of my blog post above!   {gluten-free, clean eating, low fat, low sugar}