Melt a knob of butter with the sugar in a frying pan. Add the apple slices and cook until golden and tender for about 3 or 4 minutes.
For the pancakes: sieve the flour and salt together in a large mixing bowl. Make a well in the centre of the flour and break the eggs into it. Whisk the eggs using a fork mixing the flour into the eggs as you whisk. Gradually the milk and water mixture, still whisking (don't worry about any lumps as they will eventually disappear as you whisk). When all the milk and water has been added, use a spatula to scrape any leftover bits of flour from around the edge of the bowl and finally whisk once more until you get a nice smooth batter.
Melt half butter in a pan. Spoon 2 tbsp of it into the batter and whisk it in, then use the rest to grease the pan. If you think the pan is too dry just add a smidge more butter. Make sure the pan is really hot to start with and then turn the pan down to medium.
Use a ladle to drop the batter into the pan and swirl it around the pan from side to side. It will only take a minute or so for one side to become golden pan. Use a fish slice or if you’re feeling brave flip the pancake over! The other side will only need half a minute so slide it onto a plate.
Stack the pancakes on a plate and keep them warm in the oven while you make more. Divide the apple mix between them and simply roll up or fold into quarters. Serve with a generous dollop of cream and a drizzle of toffee sauce.