Ham and cheese croquettes with mayo

1) For the croquettes, make a white sauce by melting the butter in a saucepan, stir in the flour and cook for 2-3 minutes, then whisk in the milk gradually to make a thick sauce. Season to taste.
2) Stir in 75g breadcrumbs, ham, cheese and parsley and mix well.
3) Refrigerate for at least 3 hours.
4) Add the oil to a deep-fat fryer and preheat to 170°C/338°F
5) Shape the filling mixture into 7cm croquettes.
6) Place the flour, beaten eggs and breadcrumbs in three separate bowls.
7) Dip each croquette in the flour, then the egg and finally roll in the breadcrumbs.
8) Deep fry in batches until golden-brown. Remove and drain on kitchen paper.
9) For the mayo, whisk the egg yolks with the mustard in a bowl and then very gradually add the oil, whisking continuously.
10) Stir through the vinegar and season to taste.
11) Serve the croquettes with the mayonnaise and a salad of your choice.