I use a variety of things for stuffing calzone. The only time I ever had a soggy problem was when I used too much ff ricotta. I always either sauteor roast the veggies before I put them in the dough. I think they would betoo runny otherwise. I like to use a cheese base (a little ff ricotta, ff mozzarella and real honest to goodness reggio parmesan - a little adds a lot of flavor and not a lot of fat) and then pile the veggies on top.
I love making calzone. They are especially great to take on hikes and picnics because they are really yummy cold. I usually make a whole wheat dough. One of my favorite kinds that I made had pesto for the sauce, some spinach leaves, mushrooms, and red onions. Also some sort of white ff or lf cheese, I forget what... I also make them with a tomato sauce and whatever veggies I can find. Last time I think I had mushrooms, fresh basil, fresh spinach, onions, and different colored bell peppers. I made them for a hike that I went on with a friend and my SO. They both liked them a lot.
I was amazed at how pepperoni-like the fake pepperoni was. It was almost too meaty for me to eat!
I cooked the mushrooms because I didn't think they'd get too mushy and because when I put raw mushrooms on pizza, it isn't as good as sauteed ones. Maybe they didn't need to be cooked.
I wasn't that impressed with the fat-free ricotta, but it was OK. I didn't use very much, so maybe I should use more (since I can't really taste it now).
Fresh spinach would be better than frozen, especially if cooked with the mushrooms. I didn't have any on hand, though.
I had problems with leakage as well. Actually, I think I was trying to spread my dough too thin, so I easily punctured it. Also, I was cramming loads of stuff into each one.
I wrap the dough around the filling like a burrito, because when I crimp the edges, it never sticks.
I like making this type of thing-dough around some veggie filling. I got the idea from those "Veggie Pockets" from Ken and Robert (I think that's the brand.) I make them with chinese veggies, indian curry, and pinto bean fillings. Then I freeze them so that when I come home feeling lazy, I can just pop them in the oven and eat. Sometimes I'll make the filling one day, and the actual pockets the next. [Susan Lehman]