In a large nonstick pot over medium heat, combine the butter and onion, and let cook until the onion is fragrant and translucent.
Add in the rice, stir to coat in the butter, and let it toast for a minute or so, stirring constantly.
Add in the wine, and let it cook until the alcohol has evaporated.
Add in the water or broth, about a cup at a time, waiting until the previous cup has been absorbed almost completely before adding more. You may or may not need it all!
Cook the risotto until it has a thick and creamy texture. Remember that for the cakes, you will want it a bit stiffer and less soupy. It will also thicken a bit as it cools.
Stir in the parmesan, mozzarella, salt and pepper, and set aside to cool completely before making the cakes. Refrigerate for a couple of hours if possible.
When ready to make the risotto cakes, set up an assembly line with the risotto on one end, followed by a bowl of the flour mixed with the garlic powder, a bowl of the beaten eggs, and a bowl of the panko breadcrumbs. Have a cookie sheet lined with wax paper on the other side to set the formed cakes.
Using a cookie/ice cream scoop, scoop out golf ball-sized portions of risotto, and flatten them into patties with your hands. Coat lightly with the flour, followed by the egg, and the panko. Set on the prepared cookie sheet.
When all patties are ready, pour about an inch of vegetable oil in a heavy skillet {I like using my cast iron skillet}, and heat over medium high until it shimmers.
Fry the patties 1-2 minutes on each side, until golden brown and crispy. Remove from the oil and set on a plate lined with paper towels to absorb excess grease.
Salt and pepper to taste, and enjoy warm!