With your chicken stock heated and the porcini mushrooms soaking. Heat oil/butter in a large saucepan and add the shallots and sliced baby portabella mushrooms. Cook 3 minutes or until the mushrooms are releasing their juice, add the garlic. Cook for 1 minute. Add rice, stir well and constantly til all the grains are coated and are turning opaque. (From stark white, to pearly white) Set a timer for 20 minutes and start. Add the wine and cook down til it's almost gone under medium high heat. Add salt and pepper, then begin adding the stock with mushrooms 1/2 cup at at time. Stir constantly and wait until the stock is almost absorbed before adding the next half cup. Watch your timer and test the rice when you have about 8 minutes left. If the rice isn't really starting to soften, you may need to add about a 1/2 cup or so of water to your stock to extend it. You want to add the stock mixture 1/2 cup at a time throughout the entire 20 minutes to coax a deep creamy flavor to your dish. When done, remove from heat and add cheese, then parsley and Greek yogurt. Adjust salt and pepper and serve right away.