In a large bowl, whisk the eggs and sugar until light and well combined.
Add the melted butter, milk, and vanilla essence, then mix well.
Stir in the flour, salt, and cinnamon (if using) until you have a smooth, thin batter.
Heat an oblietjie iron over medium heat and lightly grease both sides.
Pour a small amount of batter into the centre of the iron and close it firmly.
Cook for 1–2 minutes per side, or until the oblietjie is golden brown and crisp.
Carefully remove the oblietjie while still warm.
Repeat with the remaining batter, lightly greasing the iron as needed.
Allow the oblietjies to cool completely before storing—they will become crisp as they cool.