Here’s the general directions for making Croquettes from my 1918 cookbook. Apparently they were quite the popular meal. A hot oven is about 400-425 degrees.
In mixing the ingredients given in the croquette recipes, have the mass firm enough to hold together, but not compact. The croquettes should be handled as little as possible in shaping. Large spoons may be used for this purpose. In order to provide a firm and well browned outer crust, the croquettes should be rolled first in sifted bred or cracker crumbs, then in beaten egg, then again in crumbs.
These crumbs shoud preferably be from whole grain bread, which may be toasted brown and hard in the oven before rolling or grinding.
Baking Better Than Frying
The usual method of preparing croquettes by dropping into boiling oil or frying in a small quanity of fat in a skillet or pan usually makes the food soggy, indigestible and unpalatable. Even when the frying is done most carefully so that a minimum of oil is soaked in the greasy crust, the complexity of the mixture renders the croquette unwholesome and difficult of digestion for most people. The best way to cook croquettes or foods that are comonly fried is to bake or roast them. They are just as palatable and far more wholesome.
Place the croquettes on a hot, buttered or oiled gridiron, baking pan or dish and bake in a very hot oven for about fifteen minutes until nicely browned. If they do not brown well on top, they may be turned.