Put 1/2 cup of dried porcini in a small bowl and cover with 2 cups of hot water and let sit for 30 minutes.
Take 2 tbsps. of flour and 1/4 cup of water and mix to a smooth slurry and set aside.
Remove the Porcini Mushrooms from water with hands feeling the pieces to ensure there is no grit. Chop Porcini Mushrooms to a small medium size and set aside. Strain liquid into a small bowl with a fine mesh strainer or coffee filter and set aside.
Heat the 2 tbsps. olive oil (or 3 tbsps. water or vegetable broth) in a medium skillet over medium-high heat. When the oil is hot, add the onions and mushrooms and cook for 7 minutes ,or until they begin to brown. Add the shallots and cook for two minutes. Add the garlic and cook for one to two minutes, or until it just begins to brown.
Add the strained Porcini liquid and the 1 3/4 cups of no-chicken broth, rosemary and thyme and bring to a boil. Reduce heat to simmer and cook for 15 minutes. It's normal for the liquid to reduce during this time, but you don't want it to evaporate too much, so make sure that the heat is low.
Strain gravy into bowl to remove solid mixture and add gravy back to saucepan and bring to a low boil. (Do not throw strained solid mixture away. Remove herbs, chop them and serve as a side dish or mix with rice, pasta or quinoa)
Add chopped Porcini Mushrooms and whisk in the flour mixture. Continue whisking until the gravy thickens. Add the salt and pepper to taste and stir for another minute.