Rehydrate dried porcini mushrooms in boiling water for 30 minutes, weighing them down to ensure they stay submerged. Reserve the soaking liquid.

Squeeze the rehydrated porcini mushrooms, chop coarsely, and set aside.

Heat 1 tablespoon of butter in a saute pan and saute sliced shiitake mushroom tops for about 5 minutes until softened. Set aside.

Heat beef broth in a saucepan until simmering. Add the reserved porcini mushroom liquid to the broth to create approximately 4 cups of simmering broth.

In a separate pan, heat olive oil and the remaining 2 tablespoons of butter.

Saute diced onions for about 8 minutes until tender and translucent, but not browned.

Add arborio rice to the onion mixture, stir, and cook for about 4 minutes until the rice is well coated and appears opaque white.

Pour dry white wine into the onion/rice mixture, stir, and allow it to evaporate completely.

Add the chopped porcini mushrooms (not the shiitake mushrooms yet) along with 1 cup of the simmering broth. Stir and cook until the liquid has been absorbed.

Continue adding broth, 1 cup at a time, stirring and simmering until the rice is tender, which will take approximately 18-20 minutes. Some liquid may remain.

Once the risotto is cooked, stir in the sauteed shiitake mushrooms, grated Parmigiano-Reggiano cheese, salt, and pepper to taste.

Garnish with chopped fresh parsley before serving.