Slice the cheese into bricks about 3 inches long, 1½ inches wide, and ½ inch thick. Set aside. In a medium bowl, whisk together the eggs and cold water. Place the egg mixture, panko, and flour in separate shallow containers (you should be able to fit a couple pieces of cheese at a time in each container).

Working in batches of two, dip the cheese pieces very briefly into the egg mixture, then into the flour, then back into the egg mixture, and finally into the panko to make a crust, making sure to firmly press the breadcrumbs onto all sides of the cheese. Lay the finished pieces on a baking sheet lined with parchment paper and refrigerate for 30 to 60 minutes.

Heat the frying oil in a large, deep, heavy-bottomed pot until a thermometer inserted reads 350°F. Fry the croquettes in the oil until golden brown and crisp on the outside. (The key is to get the cheese soft but not liquefied. To test doneness, remove a croquette and pat dry with a paper towel. Press lightly; the crust should be firm and crisp, with a bit of give on the inside.) Transfer to a baking sheet lined with paper towels to drain. Serve croquettes as is or with a side salad of greens drizzled with tarragon vinegar and olive oil.