Start by preheating your waffle iron.
Make sure it's hot enough for a quick and even cook.
In a large bowl, mix together the flour, sugar, baking powder, and salt.
Combine these dry ingredients thoroughly.
In another bowl, whisk the milk, egg yolks, and vegetable oil until fully blended.
Combine the wet ingredients smoothly.
Gently pour your wet mixture into the dry ingredients.
Stir until just incorporated for a smooth batter.
Fold in the chopped pecans gently to avoid overmixing.
Be careful to keep the batter light.
Pour 1/2 cup of batter into the preheated waffle iron.
Cook until the steam stops and the waffle is golden brown, about 3 to 5 minutes.