Add flour while on a low heat. Quantities are approximate as I add as much as the butter absorbs. When the mixture stops sticking to the pan I consider it ready as for bechamel sauce but I add a bit more flour to make sure is thick enough to shape the croquetas.

Add the milk slowly specially at the beggining making sure it doesn't clump. Stir well

Add a pinch of salt and the dissolved cornflour dissolved in some milk. Let the sauce bubble a bit while it thickens

Add ham. (or your desired filling. My mum used to use chicken meat. I use serrano ham, crabmeat...) and mix

Let mixture cool in the fridge for a couple of hours until you're ready to shape croquetas

With the two spoons shape a bullet of the mixture

Pass bullet shapes of bechamel mix to beaten egg bowl. Máx three at a time

Coat them after with breadcrumbs

They are ready to deep fry in plenty hot oil. Or to freeze as I do for later use