Preheat the oven to 180ºC / Gas 4. Place 14 muffin cases on a baking tray and set aside.
In a bowl, beat the eggs with the vanilla essence.
In another bowl sieve the flour, baking powder and salt together.
In a large mixing bowl, with an electric hand mixer, mix together the margarine and sugar until light and fluffy. Add eggs and vanilla essence and mix well. Add half the flour mixture and mix together. Add the milk and stir. Add the remaining flour mixture and combine and set aside.
To make the caramelised apples, melt the sugar and butter in a saucepan over a low heat, add the cubed apple and cinnamon and stir constantly until the apples begin to soften (don't let them go mushy).
Divide half the muffin mixture around muffin cases. Top each cake with a teaspoon of the caramelised apples and juice, then cover each cake with the remaining muffin mixture.
Place in the centre of the oven and bake for 20-25mins, until golden.