Suggestion for veggie main to go with dauphinoise potatoes please

[BusyFrizzyLizzie]

I'm going to be cooking for a crowd of 10, one of whom is veggie. My menu is:

• Roast aubergine and tomato soup with aoili
• Roast sirloin with dauphinoise potatoes and a green salad
• Poached pears with some kind of cream/ice cream accompaniment.

I'm very happy to make my veggie guest an alternative main course to replace the beef, but have run out of inspiration. I considered roast cauliflower steak, but they always look a bit sad. However, I'm happy to be told I'm wrong!

Any suggestions gratefully appreciated. I don't think my guest eats fish, so veggie only please. Bonus points for things which can be prepared in advance. Thank you!

This is lovely, can be made in advance and just needs warming on the day.

https://www.bbcgoodfood.com/recipes/melty-mushroom-wellingtons

A veggie Wellington of some sort. Warming & autumnal 🥰

With that, I’d make myself stuffed portobello mushrooms, stuff with lentils and goat’s cheese or feta, tomatoes, garlic and herbs. Just make sure any cheese is made with vegetarian rennet.