Make the buttermilk: add ½ cup milk to a glass. Stir in 1 tsp of lime juice. Stir and let it stand for 5 mins, then use.
Melt the butter in a saucepan or in the microwave.
Add all the wet ingredients to a bowl: milk, buttermilk, eggs, and melted butter. Whisk to combine. (Retain the butter bowl; use the remaining butter in it to brush the waffle iron before cooking the waffles).
Add all the dry ingredients to another bowl and stir it around. Make a well in the centre and pour in the wet ingredients. Using a spatula, stir gently and just so they are combined. (Note: Over-working the batter will make the waffles dense, so avoid stirring any more than necessary). Rest the batter in the fridge for 10 mins. Heat the waffle iron whilst the batter rests.
Brush the iron with a tiny bit of butter on both sides. Dollop a ladle of batter onto the heated waffle iron and cook until golden. (Follow the manufacturer’s instructions.)
Rest the cooked waffles in a preheated 120 C oven while you make the rest. This is an optional step, but ensures that they stay crisp until you’re ready to eat them.
Serve with topping(s) of choice.