Have you googled “ways to use up leftover Christmas pudding”? You probably have, but it’s just a thought. Perhaps have a small amount at a time (steamed really well and maybe softened with some alcohol or boiling water) to be served with some stewed fruit - apple &/or pears would go well with it. And of course some custard or cream. Or maybe a Christmas pudding trifle, with a small amount as the base, steeped well in sherry? I love Christmas pudding, but not the hard, claggy type, so I know where you’re coming from. I certainly wouldn’t want to upset my friend, it’s not worth the embarrassment to you both or the hurt it would bring her. She’d be upset if she knew that after all these years you didn’t like Christmas pudding. There’s also merit in honesty being the best policy, but I think that diplomacy also has a part to play, so it’s a tricky one! If all else fails and as others have said, give a little bit to the birds (but not if you have a dog!)