In a large bowl, whisk the eggs and the vanilla. If you want to use a hand mixer to make them airy, the waffles will have a lighter texture.
Add the milk and butter, and whisk to combine. Add the flour, sugar (if using), baking powder, and salt. Mix until you have a smooth batter and there are no clumps but do not overmix.
Add the chocolate chips, and mix to combine.
Preheat your waffle iron and spray (if needed). Pour batter into the hot waffle iron and cook until golden brown. Remove and serve hot with butter and syrup or desired toppings.
Notes
Gluten-Free: make this recipe gluten-free by using a 1:1 gluten-free all-purpose flour. Dairy-Free: make this recipe dairy-free by using a milk alternative (same amount) and vegetable oil instead of butter (same amount).