"after supper" is a correct and usable phrase in written English.
You can use it to refer to the time following a meal. For example, "After supper, we went for a walk down to the lake."
THE OTHER NIGHT, MY WIFE AND I SPENT A WHOLE HALF HOUR AFTER supper savoring a red wine at its mellowed best, a 1982 Faustino V Reserve, whose longevity is a remarkable performance for a Rioja.
After supper he drove on toward Jacksonville.
After supper, there's jazz and dancing.
After supper it stopped snowing.
After supper they went to Dutch's place.
General Jackson came about eight o'clock, and retired after supper.
I stared at my photograph of it long after supper.
After supper one night, we went to the ocean.
Mexican's not only perfect for late-night and lunch time, exclusive and highly sought-after supper clubs have slowly started to pop up across the capital too.
"He might know some of the issues," Mr. Delis said, while taking an after-supper drive.
Maggie, out for a swim, "had her back to the shore, eyes out to sea, floating past the breakers in the mild after-supper surf.
