Step 1

At least one day before you plan to make the katsu, cut a slit in the package of tofu and drain out as much water as you can. Then, put the package of tofu in the freezer until it is frozen solid.

Step 2

Set the block of frozen tofu on a wire rack with a weighted tray on top. Jars or cans work well as weights. You may need to partially defrost the tofu first to keep the tray from slipping off.

Step 3

While you wait for the tofu to press, make the katsu sauce by adding the sake and apple juice to a pot and boiling the liquid until it becomes thick and syrupy (about 8-10 minutes). Add the remaining sauce ingredients and continue boiling it until the grated onions dissolve and the sauce is nice and thick.

Step 4

Drain off all of the liquid that comes out of the tofu, and then slice the block in half horizontally.

Step 5

To season the tofu, dissolve the Marmite in the vegetable stock and use a pastry brush to brush the mixture onto every tofu surface. You won't need all of the liquid, but make sure you get a good coating on the tofu.

Step 6

Add the flour and cold water into a flat-bottomed container that's large enough to hold a tofu cutlet and mix it until it's smooth and free of any large lumps. Next, prepare a second container by filling it with panko.

Step 7

Dip the tofu katsu in the batter, coating all sides, and allow any excess batter to drip off.

Step 8

Transfer the tofu to the panko and scoop some panko on top. Shake the whole container to distribute the panko evenly, coat the sides, and repeat with the other cutlet.

Step 9

Prepare a wire rack by lining it with paper towels and preheat 1-inch oil in a high-sided pot to 340°F (170°C).

Step 10

Carefully lower the vegan cutlets into the oil and let them fry on one side for 2 minutes.

Step 11

Flip the katsu over and fry it for another 2 minutes. Continue flipping and frying until the panko is golden brown. Drain the tofu katsu on the prepared rack. Slice and serve with the homemade katsu sauce.