Chop the onion. Heat some oil in a frying pan and stir-fry the onions until soft. Let cool.
Spread the panko on a baking sheet. Bake at 200°C for about 4 minutes.
Mix all the panko around once, then bake for an additional 4 minutes or until golden brown.
Spread out the panko in a shallow dish or pan and let cool.
In a bowl, combine the meat and the ingredients marked with 〇. Knead until very sticky.
Add the onion and the ingredients marked with ☆ and knead well. When sticky, divide in half, and shape into round patties that are larger than the buns.
Dredge the meat patties in the flour, egg, then panko. Lightly sprinkle oil over the entire patty. Put a wire rack on top of a baking sheet and set the breaded patties on top. Bake for 12~14 minutes at 230℃.
Spread butter on the insides of the bread, then spread mayonnaise on one slice.
Shred the cabbage, put into a heatproof bowl, wrap lightly with plastic wrap, and heat in the microwave (600W) for about 50 seconds to wilt.
Put the cabbage on top of the mayonnaise, then the sauce, then the baked menchi katsu, then the sauce, and close with the other slice of bread. Press down a bit on the bread.
Cut off the crusts if you like, then cut the sandwich in half, transfer to a plate, and enjoy!
You can freeze leftover panko in an airtight bag. Use as-is when you need to.
Story Behind this Recipe
This is part of a non-fried series! I adapted Menbaa's recipe by adding mayonnaise and ketchup!
Originally, the recipe used one egg for the coating, but just half does the job! When kneading the meat, it should become sticky. But, if it's not too thick, try chilling it in the refrigerator a bit! For the rack, you can use a rack for draining oil from fried foods. Please adjust the temperature and baking time according to your oven!