In a small bowl, whisk together ketchup, Worcestershire, and soy sauce until smooth. Don’t skip whisking—lumps are not your friend here.
Add sugar, garlic powder, onion powder, ginger, and pepper. Whisk again until the mixture gleams like a shiny new spoon.
Taste and adjust. If you want more tang, splash in a little more ketchup or a dash of vinegar. If you want sweeter, add a touch more sugar. You’re the boss here.
If you’re using hot sauce, fold it in now. Start small; you can always add more heat, but you can’t take it out once it’s in.
Let it rest for 5–10 minutes. This gives the flavors time to mingle and get comfortable with each other.
Serve immediately with your crispy katsu, or store in the fridge for up to a week. It loves being neglected in the fridge as much as you love leftovers.
