- Hands-onabout 5 min
- Choppingnone
- Keeps in the fridge up to a month
Keto tonkatsu sauce is three ingredients and a jar, plus an optional spoonful of sweetener. Measure, stir, done. That’s about five minutes, no chopping, no stove and one jar to wash.
It’s the thick, sweet-savoury sauce that goes on crumbed pork cutlets, and it’s just as happy on Japanese-style fried chicken. Traditional versions lean heavily on sugar, so this one uses sugar-free ketchup. Short on spoons? A bought bottle works too. See the No Spoon Swaps below.
Can I manage this today?
- Spoon level: Low Spoons. Easy to make, but a sauce is a nice-to-have, so on a no-spoons day buy a bottle instead
- Hands-on time: about 5 minutes (no hands-off time)
- Main effort: measuring four things into a jar
- Chopping: none
- Standing and attention: none. No heat and no timers
- Thinking load: one step, no timers
- Washing up: one jar, which is also the storage jar, plus measuring spoons
Quick spoon check
- No-spoons version: buy a bottle of tonkatsu sauce and check the carbs per serve on the label.
- As written: measure four things into a jar and mix. There isn’t an easier homemade version.
Kerry’s notes
Tonkatsu sauce is what makes a crumbed pork cutlet taste like dinner out. The traditional version leans heavily on sugar, so I keto-fied it with sugar-free ketchup, Worcestershire and oyster sauce. Golden monkfruit sweetener is optional.
I made a jar, stuck a label on it and took a photo. It looked far too official for four tablespoons of ketchup. It keeps in the fridge for up to a month, so one jar goes a long way.
Nutrition is Leigh’s department. Her keto vs low carb guide has the detail, and I’ll stay in the kitchen with the jar.
What’s that ingredient?
Oyster sauce. A thick, dark, salty-sweet sauce made from oyster extract. It gives this sauce its savoury depth. Look in the Asian aisle at the supermarket. Check the label for how to store it once it’s open. Easiest swap: a vegetarian oyster sauce, such as Ayam Vegetarian Oyster Sauce. Woolworths tends to stock it.
Golden monkfruit sweetener. A brown-sugar-style sweetener sold as a brown sugar replacement. It adds a depth of flavour, but it’s optional. Classic monkfruit sweetener or another sweetener will work. You just lose some of that depth.
Why this recipe works
- No heat and no timers, so there’s nothing to watch.
- The jar is the mixing bowl and the storage container, so there’s one thing to wash.
- One batch makes 8 serves, 1 tablespoon each.
No Spoon Swaps
- Bought tonkatsu sauce: skips the measuring. Woolworths sells Kikkoman Gluten Free Tonkatsu Sauce (235 g). Trade-off: the label shows 5.5 g carbs per 18 g serve, which is more than this version, so check the label against your own plan.
- Skip the golden monkfruit: saves one measure. Trade-off: you lose some depth of flavour.
- Pick a jar you can open easily: any lidded container that holds about 200 ml works. Trade-off: wide-mouth jars are easier to spoon into, narrow ones pour better.
Dietary swaps
- Regular tomato ketchup: works, but the sauce is no longer keto.
- Another sweetener: classic monkfruit sweetener or another sweetener will work in place of golden monkfruit, with less depth of flavour.
- Vegetarian: use Beerenberg Worcestershire sauce and Ayam Vegetarian Oyster Sauce. Woolworths tends to stock the Ayam one. Asian mushroom sauces are a good alternative to oyster sauce. Check the labels, because products change.
Allergen notes
- Fish: Worcestershire sauce usually contains anchovies. Check your label.
- Shellfish: oyster sauce is made from oysters.
- Soy and gluten: oyster sauce and Worcestershire sauce commonly contain soy and wheat or barley. This recipe isn’t labelled gluten free, so check your brands.
Storage, freezing and reheating
- Fridge: keep it in a lidded jar in the fridge, at 5°C or below, for up to a month.
- Freezer: not tested.
- Reheating: not needed.
Serving ideas
- Crumbed pork cutlets (tonkatsu)
- Japanese-style fried chicken (karaage)
- Fried prawns (ebi fry)
- Our Edamame & Halloumi Okonomiyaki
- Our Cheese Stuffed Kentucky Chicken Ballies, for dipping.
Frequently asked questions
What is in keto tonkatsu sauce?
Sugar-free tomato ketchup, Worcestershire sauce, oyster sauce and an optional spoonful of golden monkfruit sweetener. Traditional tonkatsu sauce usually starts with Worcestershire, soy sauce and sugar, so the sugar-free ketchup is the main change.
How many carbs are in this sauce?
About 1 g of carbs per serve. One serve is 1 tablespoon and a batch makes 8.
Is this sauce vegetarian?
Not as written. Worcestershire sauce usually contains anchovies and oyster sauce is made from oysters. Use the vegetarian swaps above and check the labels on your brands.
Can I leave out the golden monkfruit?
Yes, it’s optional. You lose some depth of flavour, and classic monkfruit sweetener or another sweetener will work instead.
Keto Tonkatsu Sauce (The Cutlet Sidekick)
Equipment
- Small glass jar with a lid (about 200 ml)
Ingredients
- 4 tablespoons sugar-free tomato ketchup
- 3 tablespoons Worcestershire sauce
- 1½ tablespoons oyster sauce
- 2 teaspoons golden monkfruit sweetener optional
Instructions
- Put all four ingredients in a small glass jar and mix well, until no streaks remain.
- Put the lid on and keep the jar in the fridge for up to a month. Use as needed.
Notes
Nutrition
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A final spoon-saving note
Make a jar this week and keep it for the next night someone fries a cutlet. Three ingredients, one jar and about five minutes. Future-you will be pleased, and so will the washing-up pile.
