Preheat your oven to 190 degrees and lightly grease a 12 hole muffin tin.
In a small jug, combine the milk, egg, oil ad vanilla extract and lightly whisk together.
Place the self raising flour and caster sugar into a large bowl and site in the liquid until the mixture has almost combined.
Fill each ⅓ of the muffin hole with mixture and add a teaspoon of jam before filling the muffin hole with a little more mixture until ¾ full.
Repeat until the remaining muffin holes are filled.
Place the muffin tray into your preheated oven and bake for 18 minutes or until the tops of the muffins spring back when touched. Remove the muffins from the oven.
In the meantime, melt the butter in a small bowl and combine the sugar and cinnamon in a small bowl.
Brush the melted butter over the top of the warm muffins and coat in the cinnamon sugar mixture.