In a large mixing bowl, whisk together the eggs, buttermilk, butter, and vanilla. Add in flour, baking powder, baking soda and salt and mix until batter is just about smooth.
Spray your waffle iron with a non-stick cooking spray and then preheat it. Use slightly more than 1/3 cup of batter (for a standard 8-inch round waffle iron). Cook until waffles are golden brown and crispy.
Slice finished waffles into quarters. Place a slice of cheese on half of the waffle pieces and place another waffle on top of each one. Place the waffle sandwiches back on the grill and heat until center cheese is melted (it's okay that your waffle iron won't be able to close completely). Serve warm.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.