I served it with Indian-style carrot salad, and blanched broccoli.
The reason, I made these potato croquettes into this form was is to conceal a button of cheese I hid inside (I used smoked Gruyere cheese) which nicely melted.
Again, there is no recipe for this. I first made buttons of Gruyere cheese (about 5x1x1cm, or whatever size depending on how the croquette would be formed). I took my wife's leftover mashed potatoes (cold from the refrigerator and easy to form) and wrapped the cheese with the potatoes and shaped in to short cylinder form or "tawara" shape 俵 in Japanese culinary parlance. I then dredged in flour, egg wash and panko bread crumbs. I deep fried in 350F oil for 4-5 minutes turning several times.
This is best eaten piping hot with the molten cheese oozing out like the picture above. My wife was delighted with the hidden cheese surprise. For intentional-leftover control, this was not too bad.