It’s not exactly like the stuff from a take away (and the ingredients are probably nothing like what goes in a Chinese curry) but the curry sauce from the Lean in 15 Katsu Curry recipe tastes similar...
https://www.google.co.uk/amp/s/amp.panmacmillan.com/blogs/lifestyle-wellbeing/joe-wicks-cheeky-chicken-katsu-curry-recipe