Place the 2 tbs. olive oil in skillet. Add onion and cook on medium-high until onions are starting to carmelize,add mushrooms. Cook until all are nice and brown but not burnt. Set aside.
In 2 quart sauce pan add orzo. Pour stock over orzo until about an inch or so above orzo. Bring orzo to a boil. Turn down to simmer and cook about an additional 5 min. until liquid looks like it is starting to slightly thicken. Add mushrooms and onions stir until mixed. add a little salt & pepper.
Take off heat, cover and let sit for 15 to 20 minutes. Orzo will absorb liquid and have creamy texture. Fluff and add resereve stock to thin if a little too thick. Add fresh chopped parsley before serving.