Melt butter in a heavy set pan, and saute the finely chopped onion.
Sprinkle flour, and saute over low heat until it's no longer floury. Take care not to let it burn.
Add milk to the pan little by little, mixing all the time with a wooden spatula, until you have a creamy sauce.
Add soup stock granules, pizza cheese, and crabmeat and mix. Season with salt and pepper.
Transfer the filling to a shallow container, and chill in the refrigerator until the sauce is set.
Divide the filling into 8 portions and form each into a patty. Oil your hands first to prevent the filling form sticking. Put the formed patties in a floured container, and put them in the freezer to firm up. This makes them easier to coat.
Coat the patties in flour, beaten egg, and panko. Leave at room temperature. Then deep fry in 375°F/190°C oil until golden brown.
Story Behind this Recipe
I wanted to use up some crab meat.
When adding the flour and milk to the pan, keep on stirring constantly. This way, you can avoid the sauce from burning or forming lumps. I divided the filling into 8 portions, but they are easier to fry if you form them into small shapes, and are less liable to burst in oil. In addition, if you fry the croquettes after breading them while the filling is still cold, they're also more likely to burst in the oil. So let them warm up at room temperature after coating them. You only have to fry the croquettes very briefly.