Preheat your waffle iron according to the manufacturer's instructions.

In a large bowl, whisk together the flour, baking powder, cinnamon, salt, nutmeg, and granulated sugar.

In another bowl, beat the eggs, then add the milk, melted butter, and vanilla extract. Mix well.

Pour the wet ingredients into the dry ingredients and stir until just combined. Gently fold in the diced apples.

Lightly grease the waffle iron with cooking spray or a small amount of oil. Pour enough batter into the waffle iron to cover the surface, close the lid, and cook until golden brown (about 4-5 minutes). Repeat with the remaining batter.

While the waffles are cooking, prepare the glaze by whisking together the powdered sugar, milk, and vanilla extract in a small bowl until smooth.

Once the waffles are done, remove them from the waffle iron and drizzle with the glaze while still warm.