Whisk together all the wet ingredients (eggs, milk, sour cream, and butter) in one medium bowl and all the dry ingredients (sugar, salt, spices, if using, and flour) in another. Slowly add the dry ingredients to the wet ingredients, stirring steadily until the wet and dry ingredients are combined. Let the batter sit at room temperature for about 30 minutes. (The batter can also be made a day in advance and kept in the fridge.)
Spray a preheated waffle iron with nonstick cooking spray, and spoon just enough batter into the iron to fill it. Close the waffle iron and cook until the waffle is brown and crisp on both sides, 3 to 5 minutes.
Serve the waffles with the toppings of your choice.