Cut or french green beans and drop them in boiling chicken broth and lemon juice just until crisp tender, 4 minutes or so. Reserving broth, remove beans to shallow casserole dish. Meanwhile in skillet, in as little oil as possible, saute onion until pretty well browned and add to beans. Repeat with mushrooms, browning over high heat for just a couple of minutes and add to bean mixture. Add jar of pimentos, salt and pepper to taste, and toss well. Bring reserved chicken broth back to a boil, reduce heat and add enough cornstarch dissolved in water to make a gravy-like sauce, stirring quickly. Pour over bean mixture, tossing lightly to coat. You may not need all the sauce. Sprinkle crushed fried onions over top. Bake, uncovered, in 350 oven for 20 minutes or so. (The above ingredients are all esimated amounts. Put as much of anything as you like. This whole thing could be speeded up by using frozen green beans and canned mushrooms.)