José Pizarro’s Spanish croquetas

Method

1. Add the spinach and a splash of water to a pan over a medium heat. Cover and leave to wilt for a few minutes, then remove from the heat and leave to cool. Once cool enough to handle, squeeze out as much liquid from the spinach as you can. Finely chop and set aside.
2. Add the milk and stock to a saucepan and gently warm. Add the butter and oil to a separate large saucepan over a medium heat. Once melted, add the 125g flour and cook, stirring, for 2-3 minutes. Gradually add the warm milk mixture, stirring constantly, until you have a smooth, very thick sauce. Season well with salt and pepper, then stir in the chopped spinach, tarragon, manchego and all but 25g of the walnuts.
3. Line a baking tray with cling film, then pour the mixture onto it, spreading it out evenly. Cover with another sheet of cling film, then cool and chill in the fridge for at least 2 hours.
4. Once the mixture is chilled and firm, add the 3 tbsp flour and the reserved walnuts to a food processor and whizz to a fine powder. Transfer to a dish, then put the beaten eggs in a second dish and the breadcrumbs in a third. Use a tablespoon to help roll the chilled, firm cheesy mixture into roughly 30g balls or barrel shapes.
5. Coat each croqueta in the walnut flour, then the egg, then the breadcrumbs. Put them on a baking sheet as you work then, when they’re all coated, put the tray in the freezer for 1 hour.
6. When ready to cook, heat a deep pan of oil to 180°C. Working in batches, fry 3-4 croquetas for 3-4 minutes until deep golden and crisp, with a gooey centre. Remove with a slotted spoon and drain on kitchen paper while you fry the rest. Serve immediately while still warm.