When you say "rich tomato basil soup" do you mean rich with cream? or only with flavor?
How about roasted veggies...red and green peppers, chunks of sweet onion maybe chunks of eggplant maybe zucchini, and a few asparagus spears for good measure..slices of baby bella 'shrooms...toss with EVOO, some Kosher salt...a bit of garlic ( if there is not a lot in other dishes) a bit of sugar, balsamic...and oregano...or parsley or rosemary or any herb that blows your dress up.
How about a side of mushroom risotto....? Oven roasted potatoes are always wonderful.....and can go into the oven before the meat.
If your soup is broth based....how about that spinach dish ( the name escapes me!!) spinach, cream, lots of fresh grated parm....bread crumbs and baked...has a woman's name!! AARGH it's hell to get old!
Peas in a little butter, oregano tarragon sauce....thickened just a tiny bit with corn starch....neeed a recipe....give a shout.
What are you saucing the beef with?....could I suggest a blue cheese/walnut sherry sauce??
Linda C

Here is a picture of a

I made not long ago. It will give you an idea of sides that go well. Rutabaga, green beans, Cauliflower with a buttered bread crumb topping. I especially like the Potato Duchesses with buttered peas. And a rich wine sauce.

Ann

Thanks for these suggestions. Ann T, what a beautiful plate you make! I'll admit I've never had a rutabaga in my life, LOL!

Linda, my soup recipe does include cream.

I was thinking of a classic bernaise with the meat, but your suggestion sounds wonderful.

Something I tried for Thanksgiving and was a HUGE hit was Herb-Marinated Mushroom and Celery Salad out of the November issue of Food & Wine. I think it would count as festive enough and an advantage is because the mushrooms are marinated for several days there's very little left to do at the end. If you're interested in the recipe just shout.

-Janet

Janet, I'd love that recipe, thanks.

For my Prime Rib & Yorkshire pudding Xmas dinner-my side dish is very festive looking and very tasty!
Baby Peas & Pearl Onions in Baked Tomato Cups
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1 large tomato per person
* Slice off the top of the tomato & (I used a grapefruit spoon)-clean out the insides-leaving more thickness on the bottom than on the sides. I also made a THIN slice on the bottom so the tomato sits perfectly even. Sprinkle with salt & turn upside down to drain well.
* You can either use frozen peas & pearl onions-or use fresh-either way-allow 10-15 min. for the tomatoes to bake at 350°, then fill with the pea mixture. I drizzle a little olive oil inside the tomato & season lightly with salt, pepper & a tad bit of garlic powder. When just tender soft-remove tomatoes & place on a serving platter & fill with the pea mixture, add a pat of butter on top & a sprig of parsley or herb of choice.

We like twice baked potatoes and roasted asparagus with tenderloin. Alexa, over on the Cooking forum, just posted a recipe for mushrooms that sounds excellent...would be a great tenderloin side.

Here is a link that might be useful: Alexa's Brandied Steakside Mushrooms