Add all-purpose flour, baking powder, baking soda, sugar and salt into a large bowl.
Whisk to combine thoroughly.
In another bowl add the whole egg and beat.
Add buttermilk and vegetable/canola oil to the bowl with the egg and stir your wet ingredients to combine.
Add your wet ingredients into the bowl with your dry ingredients and stir just long enough that you no longer see dry flour. This batter does not need to be super smooth a few lumps are ok.
Leave the bowl on the counter while you wait for your waffle maker to come to temperature.
I typically use a heaping 1/4 measure to scoop out my waffles into the waffle maker. Waffle makers are different, so you might need more or less for a perfect waffle.
Once your waffle is cooked according to the device specifics, or once it has turned your favorite shade of tan/brown, remove from the heat to a sheet pan or cookie pan and place in a 200-degree oven to keep the waffles warm until the rest are finished cooking.