Step 1

Gather all the ingredients.

Step 2

Wash the potatoes under cold running water. Peel the potatoes with a vegetable peeler and remove the eyes.

Step 3

Cut each potato into equal 4 pieces. Tip: To cook evenly, it's important that they are in a similar size.

Step 4

In a large pot, put water and potatoes and bring it to a boil covered on medium heat, leaving the lid slightly ajar to prevent from boiling over. It will take about 15 minutes to a boil. Cook potatoes until a skewer goes through the potato easily, about 15-20 minutes.

Step 5

Meanwhile (you have about 30 minutes till the potatoes are ready), chop the onion finely. With the knife tip pointing toward the root, slice the onion to within ½ inch of the base. Make about ¼ inch parallel cuts. Then slice the onion horizontally about ¼ inch parallel cuts.

Step 6

Then cut perpendicular to the first slices you made. If the onions need to be chopped finer, you can run your knife through them in a rocking motion. Be sure to hold down the tip of the knife; otherwise, the onions are going to go flying around the room.

Step 7

In a large skillet, heat oil on medium heat and add the chopped onion.

Step 8

Saute the onions until translucent and tender, about 12-15 minutes. Tip: Make sure there is no moisture left so that the croquette doesn't get soggy. Leave the chopped onions for a long stretch between stirring to give them nice char. Careful not to burn.

Step 9

Add the meat and break it up with a wooden spoon.

Step 10

Season the mixture with salt and black pepper.

Step 11

Stir to combine, turn off the heat when the meat is no longer pink. Remove from heat to let cool slightly.

Step 12

Once in a while, you have to check if the potatoes are done cooking. Insert a skewer to a bigger piece of the potatoes and if it goes through the potato easily, it's done. Remove the potatoes from the heat and drain the water completely. When you do so, use a lid to cover so the potatoes don’t fall out from the pot.

Step 13

Move the pot back to the stove. Shake the pot over low heat and let the remaining moisture completely evaporate (but don’t burn the potatoes), about 2-3 minutes. Then transfer to a large bowl.

Step 14

With a potato masher, mash the potatoes while they are still hot and let the steam escape. Add the butter. Tip: Keep some potato chunks for texture.

Step 15

Add salt and pepper and combine well together.

Step 16

To avoid adding excess cooking liquid from the meat mixture to the mashed potatoes, gently squeeze the liquid out from the mixture by collecting it to one side of the pan.

Step 17

Add the meat mixture into the mashed potatoes in the bowl and combine together.

Step 18

While the mixture is still warm, but not hot, start making the patties (traditionally, oval shape, roughly 3-inch in length), avoidng air pockets.

Step 19

Cover and let the Korokke patties rest in the fridge for 15-30 minutes (Do not skip!). TIP: Resting and cooling down the patties prevents the croquettes from exploding while deep frying. The cold patties in the hot oil will not release any steam; therefore, croquettes will not explode in the oil. If you skip this process and the patties are still warm, the temperature of the patties will go up and start to steam, which will then puncture a hole in the panko coating and explode. It also helps the ingredients to meld together.

Step 20

Prepare a tray each for flour and panko, and crack eggs into a small bowl.

Step 21

Coat each patty in flour and shake off excess.

Step 22

Then dredge in egg and coat with panko.

Step 23

Once you finish coating the patties, add the oil to a medium pot. Make sure there are at least 2 inches (5 cm) of oil in the pot so the entire croquette will be covered.

Step 24

Bring the oil to 340-350ºF (171-178ºC) over medium heat. Use a cooking thermometer to check the oil temperature (no guessing!). Once you get used to deep-frying, you can use the chopstick or panko tricks to determine the oil temperature.

Step 25

Deep fry 2-3 croquettes at a time until they are golden brown, about 2-3 minutes. Tip: Do not touch the croquettes until one side is golden brown. The inside is already cooked, so all you need to do is to fry until golden brown!

Step 26

Transfer the croquettes to a wire rack or paper towel to drain excess oil.

Step 27

Serve the croquettes with Tonkatsu sauce (my homemade recipe). Typically, deep-fried foods are served with shredded cabbage in Japan.

Step 28

You can store the leftover in an airtight container and freeze up to a month. To reheat, put the defrosted or frozen croquettes on a baking sheet lined with aluminum foil or parchment paper. Bake at 350ºF (180ºC) for 15-20 minutes for defrosted ones or 45 minutes for frozen ones. Check if the inside is warm before serving.