You'll get the standard TATL PE service which is for a Eastbound overnight - full bar service after takeoff then a full meal with starter, main, dessert, cheese all served on one tray. Choice of main dish. The fact you're taking off at 10pm (or later) isn't really relevant!
Then before landing a smaller tray of fruit, yoghurt but with a main course option that includes a hot dish.

Westbound back to IAD it'll be similar but instead of the breakfast there'll be an afternoon tea.

Here's a Eastbound service leaving JFK at 11pm.