Preheat and Prepare: Turn on your waffle iron to preheat according to the manufacturer's instructions. A hot iron is key for a crisp exterior. Place a wire rack over a baking sheet in your oven and set it to a low temperature (around 100°C) to keep the finished waffles warm.

Combine Dry Ingredients: In a large mixing bowl, whisk together the plain flour, caster sugar, baking powder, bicarbonate of soda, and salt. This ensures the leavening agents are evenly distributed.

Mix the Wet Ingredients: In a separate, medium-sized bowl, whisk the two egg yolks. Then, whisk in the room temperature buttermilk and vanilla extract until just combined.

Melt the Butter: Gently melt the 115g of unsalted butter in a small saucepan or in the microwave. Allow it to cool for a minute or two, then slowly whisk it into the buttermilk and egg yolk mixture.

Combine Wet and Dry: Pour the wet mixture into the bowl with the dry ingredients. Gently fold them together with a spatula until they are just combined. A few small lumps are perfectly fine – do not overmix, as this will result in tough waffles. Let the batter rest for 5 minutes.

Whip the Egg Whites: While the batter rests, place the two egg whites in a clean, dry bowl. Using an electric hand mixer or a stand mixer, whisk the egg whites on high speed until they form stiff peaks. I find this usually takes 2-3 minutes. You'll know they're ready when you can lift the whisk out and the peak holds its shape.

Fold in the Egg Whites: Gently fold the whipped egg whites into the waffle batter using a spatula. Work in thirds, using light, lifting motions to incorporate them without knocking out all the air you just created. The batter should be light and airy.

Cook the Waffles: Lightly grease your preheated waffle iron if required. Pour the recommended amount of batter onto the centre of the iron (check your manual, but it's usually around 120-180ml per waffle). Close the lid and cook for 3-5 minutes, or until the waffle is deep golden brown and crisp. The steam will reduce significantly when it's nearly done.

Keep Warm and Serve: Carefully remove the cooked waffle and place it on the wire rack in the warm oven. Repeat with the remaining batter. Serve the waffles hot, topped with a generous pat of butter and a good drizzle of real maple syrup.