Oh, soundsd lovely!

As for vegetarian soups, there was one I had last Valentine's Day at Davio's, a really lovely tomato-basil soup with pastina ... maybe something like that?

I'd also suggest French onion, using a veggie stock rather than beef stock, but that might not mesh well with the lasagna.

estherchaya has the recipe for a pretty darn good tomato soup that I emailed to her. I'd send it myself but I cannot find it right now.

It's easy and delcicious!

The problem is, I'm serving lasagna. I'd rather not have two tomato sauce dishes.

You are correct. That would be way too much tomato!

Pea soup? Potato-leek soup? Some kind of lemony-spinach soup?

Or miso with tofu and some vegetables you're not using in the lasagna (carrots?)

basingstoke makes a killer mushroom and barley soup. might be a bit heavy before lasagna, but just the mushroom part alone (no barley) would be really good, too.

I think I would vote for Exciting Mediterranean Antipasto (roasted veggies, pepperoncini, stuffed grape leaves, stuffed olives, hummus-type spread, pita and random cracker flatbreads) or a salad (with perhaps a few Exciting Mediterranean ingredients) instead of soup; lasagna's a pretty substantial dish on its own. But since it's out in the sukkah, and in case it's cold... maybe one of the butternut-squash-with-dairy variants out there, flavored with a sweet basil if you can find one? It's pleasantly harvest-y, and I think it could mesh nicely with a vegetable-heavy lasagna. Alternatively, something light with veggie broth and lemon juice and fresh wilted baby spinach and really good fresh-grated parmesan and possibly a smidge of pastina... couldn't hurt. Or you could make tomato soup and spinach/cheese lasagna -- I have an excellent recipe if you don't have one handy. :)

It's going to be in the low sixties at best out there. I plan to serve salad anyway. I like that second idea - any recipes for that? Or a garlicky one?

I might look at something oniony-garlicky, and light, to lead into but still contrast with the lasagna. Maybe use a celery stock instead of beef?

Conversely, gazpacho, though based in tomatos, is very different from lasagna -- but still might connect with the palates of your diners.

Just a couple of pence from a still-learning cook. :-)

Good luck!

Gazpacho's main problem is that it's *cold*. We're eating this in a shack in the backyard.

I was thinking about a garlicky spinach soup. (And heating up some alphabet soup for the three-year-old.)

Carrot and Orange soup.
Not as heavy as a pumpkin or potatoe-leek, and a lovely warm color. It is also a contrast to the garlic/basil flavours you will already be using in your pasta.
Method: Cook carrots in Vegie stock, blend, add orange rind to taste. Finish with some orange juice before serving.
Add a bit of ground coriander or cumin if you want to give it more depth, or alternately some fresh coriander leaves.
(Coriander=Cilantro)
Hope you dont mind comments from strangers- your food description was just way too inviting, and I had to give my opinion!

Could I do this ahead of time? I can't use a blender on yom tov.

I'd say something about the three year old, but I think I just might heat up some canned alphabet soup for her anyway.

My usual attitude to soup is to make a big batch, eat some, put the rest away, (In the refrigerator obviously)take it out the next day, maybe tinker with the flavour at bit..So I would say YES, please make it before hand.
HOWEVER please be aware that the flavour from the orange rind especially will develop over 24 hours as you store it, as the oils from the orange rind will permeate the soup.
I had one batch of this soup that ended up tasting-well- a bit TOO orange.
So use a light hand with the orange rind early on, and maybe have some orange rind pre-mixed with unsweetened yogurt or sour cream that you can dob on the top of the soup before you serve.

Some pre-ground white pepper might also be useful to help balance the flavours at the last moment (or the aforementioned cumin/coriander/cilantro)
Sorry I cant give you exact measurements, I'm not an exact cook.
Best wishes!