2 tbsp unsalted butter
2 leeks, washed, halved lengthwise and thinly sliced
100 old cheddar
1 tbsp wholegrain mustard
Heat the butter in a non stick frying pan over a low medium heat and gently fry the onions with a pinch of salt for 10 mins until softened. Tip into a large bowl and cool. Whisk in the eggs, flour, cheddar, mustard and plenty of seasoning, then gradually stir in the milk until you have a thick batter.
Heat more butter in a non stick frying pan and drop in 2-3 heaped tbsp of batter. Cook for 2-3 mins or until golden, then flip and repeat.