Whisk the eggs in a large mixing bowl, then add the flour, sugar and milk and beat until smooth. The batter should be thick enough to slowly drop off the spoon.
Heat a little sunflower oil in a griddle or heavy bottomed large frying pan over a medium heat. Pour the batter in large spoonfuls to make each pancake leaving plenty of room for them to expand.
The pancakes are ready to turn when bubbles rise to the surface and break, like the holes in a crumpet. Adjust the heat to keep them from browning too much. Flip the pancakes over and cook for about two minutes. If you're making a large batch, they keep warm only for about 15 minutes.
For the Dutch fried apples, heat butter in a small saucepan over a medium heat. If your apples are very tart add a little icing sugar to the butter and cook until the sugar is melted.
Add the chopped apple and cook, stirring occasionally, until tender and golden brown. Pour in half the advocaat and let it bubble down and reduce to a scant coating.
Serve the pancakes topped with the apples and a drizzle of the remaining liqueur.