Pound your chicken thighs out using a meat mallet or a rolling pin. You want the thighs to be pounded thin so that they cook evenly. Once they are pounded out, sprinkle  the seasonings over each thigh so that they are fully coated (front and back).

Now heat up a large skillet over medium heat, and add your vegetable oil into it. While the oil is heating up, set up your dredging station. 

Add your flour to a shallow dish, then add your beaten egg mixture into a separate dish, and your panko bread crumbs into another dish. 

Fully coat your chicken thigh with the flour, then dip it into the egg mixture, then into the panko crumbs. Press the panko into each side of the chicken thigh so that it sticks well. 

Then place the breaded chicken on a cooling rack, or a piece of parchment paper to let the breading set while you continue breading the other thighs.

Once all of the thighs are breaded and have sat for at least 2-3 minutes (to allow the breading to stick to the chicken), gently place them into the hot oil, one at a time. Do not overcrowd your skillet!

Fry them on each side for about 4-6 minutes, or until they are golden brown. The chicken should reach an internal temperature of 165ºF when it is cooked through. 

Once the chicken is cooked through, remove it from the oil and place it on a clean cooling rack to drain the excess oil. Continue this process until all of the chicken katsu has been cooked. Serve right away, and enjoy!