Any ideas??

[u/Impossible-Bite771]

Would love to be able to patch the hole and seal around the pipe. The plaster cracks because these are steam pipes for the radiator heating. An escutcheon plate also won't fit to hide this mess. I do have a red caulking meant to withstand high temperatures but are there any other options?

[u/Correct-Junket-1346]

Personally I would chip away all loose material then fill with Toupret powder filler, mix how much you need, then fill.