This is all done "by feel" so adjust proportions as you like:
1 c. green beans (this should be the "primary" ingredient, in the ratio)
1/2 to 1 onion (sort of to taste)
3-8 oz mushrooms (just keep chopping until there's as many as you like)
Mix these together. Take a look at it and see if you like the ratio of stuff to stuff. If not, add more of whatever lacks.
1 Tblsp. onion soup mix (some have a lot of garbage in them. read labels carefully.)
1/4 c. Unflavored soy milk (I accidentally used vanilla once. Not recommended.)
Mix well, and pour over the veggie mix. (This ratio works, make enough to moisten everything.) Stir to coat everything.
Sprinkle with soy parm, add a health friendly version of French's fried onions if you like (I often leave them off). Cover.
Bake 350o for approximately 1/2 hour. Stir occasionally to make sure everything stays coated. (The one difficulty I have with this is that the sauce is fairly runny, especially when it's hot.)