Deep-fried tofu in tempura sauce 揚げ出し豆腐

Deep-fried tofu in tempura sauce 揚げ出し豆腐 (Mark's book p21)

This is a favorite Izakaya "teiban" 定番 or regular dish. It's called "agedashi-dofu" 揚げ出し豆腐 ("a-ge" means "deep fried", "dashi" means "broth"). Our good friends told us that they had this dish in a small Japanese restaurant located in a remote mountain town in the Western Canadian Rockies last summer (a very unexpected place to find good Japanese food). They liked it very much. So much so, they tried to make it at home. They said that the broth came out OK but the crunchy surface of the tofu was missing from their version. They said they coated the tofu with corn starch and pan fried it, instead of deep frying it. I have not made this dish for some time since we can have it at our Izakaya substitute in the U.S., "Tako Grill", which we frequent. They make a very good agedashi-dofu.

There are many versions of the recipe for this dish but the most important factor for its success appears to be the quality of tofu followed by the kind of flour used to coat it. I have traditionally used "potato starch" 片栗粉. That is also used in the the recipe in Mark's book. Potato starch is available in our Japanese grocery store. Other recipes suggest the use of regular AP (all purpose) flour or coating the tofu first with a beaten egg before dredging it in the flour. Most of the recipes call for deep frying the tofu but some home recipes suggest pan frying.

I decided to do a small experiment. After draining and removing the excess water (as described before) from a firm or "momen-goshi" tofu, I cut the tofu into 8 equal sized rectangles and remove any surface moisture using paper towels. Four rectangles were coated with potato flour. Two each were coated with corn starch or AP flour. I usually deep fry these but our friends appeared to want to avoid deep frying. I do not think pan frying can give a nice crunchy surface to all sides of the tofu. So, I decided to use a "shallow frying" technique. The amount of oil I used is somewhat more than pan frying but much less than deep frying. The depth of the oil came to just half the thickness of the tofu as you can see below. Probably, I can further experiment to see how much more I can reduce the amount of oil while still maintaing the crunchy crust.

I used a frying pan large enough that the tofu pieces do not touch each other (otherwise they will stick together especially if you coat them with potato starch). They were cooked together in the same pan for the same amount of time. (Actually, I did two runs. The potato starch coated tofu was included in each run as a reference). I turned over the tofu once half way through the cooking (4-5 minutes each side or until the bubbles become small).

In the picture below on the left, the ones in the front were coated with potato starch, the ones in the back with AP flour (all are same size but the ones in the back look smaller because of the perspective of the camera lens). In the picture on the right, the lighter one (left) is coated with potato starch and the darker one (right) is coated with corn starch. The results were very clear; the potato starch does not burn and forms a nice crunchy surface crust with a very unique inner layer of somewhat gelatinous texture. 

The corn starch is the second best. It does result in a darker color surface than does the potato starch but the crust in nicely crunchy. My wife also noticed that the corns starch imparts a subtle corn flavor to the tofu. The tofu coated in AP flour burned easily and did not form a good crust. So, my conclusion is that potato starch is the best and corn starch is OK but AP flour does not work. So for this dish 1) use potato starch but corn starch can also be used, 2) use either "deep" or "shallow" frying.

The broth is the usual mixture of dashi, soy sauce, and mirin but I took a short cut, and used a good quality bottled concentrated broth which I just diluted with hot water (to your desired taste). I added a small amount of soy sauce because it was a bit too sweet. For this dish, I make the broth stronger than I would if I were using the broth for a warm noodle dish. I just garnished it with grated ginger and chopped chives or scallions but you could also add any combination of julienned nori sheet, bonito flakes, graded daikon, prepared mushrooms, or even thicken the broth with potato starch (then, the dish is called "agedoufu no ankake" 揚げ豆腐の餡かけ, which is similar to "Deep-fried tofu with Mushroom sauce", Mark's book p120).