I like Trader Joe's no boil noodles, and I also roast my veggies before adding to the lasagna -- it enhances the flavor.

I love to do butternut squash, mushroom and ricotta. I tend to skip the bechamel. If doing a tomato sauce lasagne I go a little light on the sauce unless I'm using no-boil noodles. Like whowantsdinner, I like to use fresh noodles, uncooked, if doing spinach and tomato sauce. Lots of layers of noodles and not so much filling - it's more like a torte and not too wet at all.

Here's a twist that might or might not appeal to you - there are many recipes out there for this, but I tend to base off of Ellie Krieger's. Whole wheat lasagna noodles, cooked and then laid out on wax paper sprayed with vegetable spray. Line them with a spinach and ricotta mixture, then some tomato sauce, and roll them up into pinwheels which you put upright into a baking dish with a little more sauce. They get a little crusty on top and look very appealing.

In fact I had to come up with a "common house" vegetarian dish a few weeks ago. I went with a roasted red pepper and ricotta lasagne. I'm not in the "no boil" camp though. I used thin flat sheets made by Rustchella d'Abruzzo who have the best factory made pastas in Italy if you can find their stuff. First you roast and peel the peppers, seed and slice them. Make a bechamel sauce. For this dish I boiled the pasta but intentionally undercooked it because I wanted crisp, crunchy at the edges. Rub a deep lasagne pan with butter add a thin layer of pasta, spread on some bechamel, lay out strips of red pepper, top with ricotta and just repeat those layers: pasta, bechamel, peppers, ricotta and so on. At the end I topped it with more ricotta and a lot of grated parmigiano. Bake at 400 degrees. Minimalist but really good. Structurally similar to what I remember eating in Modena.

I haven't done this yet but I have some porcini mushroom powder which I intend to test in fresh, housemade lasagne sheets. This one will get a mushroom filling. Maybe even some truffle in there.

Lots of great info hear but I don't know if I saw anyone talk about using salt to draw the moisture out of your vegetables before cooking and then saute to get a nice carmelization or roasting under the broiler would also help. If your adding mushrooms, are you washing them with water? try to precook vegetables with as little oil or butter as possible. There is a technique for mushrooms that is is some times jokingly called sqeeling the shrooms or letting the smurf out. Where you add sliced mushrooms to a dry pan and let them cook until they sqeel. This is the sound of steem leaving the mushroom and the intention is to remove all moisture before suate'ing. Maybe try that with thin sliced vegetables.

I use the Barilla no-boil noodles with great success. They soak up a lot of liquid.

The eggplant sounds like a great solution, too! Slice thin, brush lightly with oil, cook just until soft.

If you use the no-boil, remember to cover the pan tightly with foil. Here's my traditional recipe using no-boil sheets. You could replace the Bolognese sauce with veggie sauce, and the bechamel with ricotta mixture, layering the eggplant in between. You could call it Eggplant Parm Lasagna! http://www.food52.com/recipes/2921_lasagne_alla_bolognese/1

I agree with not boiling the noodles. If you're scared to put dried hard noodles (I was at first) soak them in hot water. That'll 1) get them soft and easy to cut and 2) help soak up the excess water in the lasagna.

I've had great success with a veggie lasagne with mushroom ragu and spinach as the filling. I use fresh lasagne noodles (no, I don't make them, but I buy them from a great source). Also, no ricotta, but a bechamel, so it's layers of noodles, mushroom ragu, spinach (frozen is fine. Just make sure to squeeze out ALL moisture after cooking it), bechamel, and lots of grated parmesan cheese. If you've cooked all the liquid out of the mushrooms for the ragu, and squeezed all the water out of the spinach, the end result won't be watery at all

what about letting the lasagna sit overnight in fridge? helps firm things up.

You can also just use regular uncooked lasagna noodles (not the no boil ones) in the dish and bake it. As the noodles cook they will soak up the juices. I just did this for the first time (scared, I have to admit) with great success. My lasagna had eggplant (grilled), yellow squash (grilled), roasted red peppers, sauteed mushrooms and onions, pesto, sliced tomatoes, and tomato sauce in it. The assembled lasagna did sit in the fridge for about 4 hours before I baked it, but I don't think that made a difference.

No-boil lasagna noodles work really well and tend to soak up a lot of the extra liquid. I tend to pre-cook all my vegetables though and used to reduce the tomato sauce (er, by heating, not by adding less) before baking too.

I'm with the others here on getting the water out of the veggies before putting them between the noodles . . . you are, of course, steaming them when you put that top layer of noodles and cheese on top. Also remember that overcooking the custard (eggs plus dairy) releases a lot of water, too. Also, what are doing with your noodles? Are they cooked at all? If so, under cook them, significantly, and they'll soak up extra moisture. And please, do, let us know how your next batch turns out! ;o)

I've done the draining ricotta and adding eggs.
I've also cooked the heck out of mushrooms and spinach and drained them.

I'm going to try the oven roasting...it's the one thing I haven't done!

I think it depends on your veggies ... do you love eggplant? I have great luck with oven roasted veggies in lasagne, eggplant being one of them, and it also acts like a sponge to soak up liquid. If you are using spinach ... cook and drain thoroughly because that may be your soupy nemesis. And as TiggyBee says - those mushrooms also need the water cooked out of them.

Without knowing your specific method, two things come to mind: Are you draining your ricotta cheese thoroughly and also have you tried adding a beaten egg or two to the cheese to help it set?

Use Ed Giobbi's Lasagna Recipe. I suspect it will be in the as yet unpublished New York Times Cookbook by Amanda Hesser and Merrill Stubbs. My copy is from the New York Times Magazine so you can probably get it from the archives. Instead of meat in the sauce, chop up a ton of mushrooms and sautee them in olive oil and garlic until a lot of the water has cooked out. Proceed. You will never be mocked again.