In a large bowl, whisk together the flour, sugar, baking powder, and salt until they're evenly combined. This step only takes a minute, but it helps prevent any clumps of baking powder from ending up in one bite. Set this bowl aside while you prep the wet ingredients.
In a separate bowl, whisk the egg, milk, vegetable oil, and vanilla extract together until smooth. Add a few drops of orange food coloring at this stage and stir until the color looks even. You can always add more coloring gradually until you reach that classic pumpkin shade.
Pour the wet ingredients into the bowl of dry ingredients and stir just until combined. Try not to overmix here, since a few small lumps are totally fine and actually keep the texture light. The batter should look thick but still pourable.
Preheat your waffle maker and lightly grease it if needed. Pour in enough batter to cover the plates and close the lid, cooking on medium heat until the indicator light goes off. If it doesn't look fully done, give it another 30 seconds before checking again.
Once the waffle is out and has cooled for a minute, use black gel icing to draw two triangle eyes and a round jack-o'-lantern mouth. Add a green icing stem at the top and press a pinch of sprinkles into it before serving right away.