Heat up your waffle iron. I use a medium heat setting on mine, which makes the exterior crunchy, but prevents the outside from getting too browned.
Combine the flours, baking soda, and salt in a large bowl.
In a second bowl, combine the melted butter, greek yogurt, milk, honey, vanilla, and eggs. Whisk all wet ingredients together until thoroughly combined.
Make a well in the center of the dry ingredients and pour in the wet ingredients. Mix thoroughly until combined. You may need a few extra splashes of milk or water to thin it out. You want the consistency to be like brownie batter.
Scoop the batter into the waffle iron and bake until done, 3-5 minutes or so, depending on what type of iron you're using. Your waffle iron will also dictate how much batter to scoop in. For Belgian waffles, I put a scant 1/4 cup into each well.
Serve immediately. These keep well in the fridge, reheated in a 350 oven for about 5 minutes.