Mix the flour, baking powder, and salt in a small bowl and set it aside.
Separate the eggs. Place the egg whites into a medium bowl and the egg yolks into a large bowl (larger bowl). Whip the egg whites to stiff peaks.
In the separate bowl with the yolks, pour in the buttermilk and vanilla, then whisk until the yolks are mixed in.
Add the dry ingredients to the buttermilk mixture and only mix to combine. At this point, you do not want to overmix the batter, there should be small lumps in it.
Next, pour in the melted butter and mix this in as well- mixing only to combine.
Last, fold in the whipped egg whites. This will add structure and a crispy exterior.
Cook the waffles in the preheated waffle maker.
To ensure you get the crispy outside, be sure to cook the waffles hot enough and long enough.
If you aren't serving these right away, layer them on a cookie sheet and place in a warm oven until you are ready to serve. i have a warm setting on my oven and use that. Although, I will say, my preference is to serve these right away while they are crispy.