Heat stock in saucepan until simmering. Maintain a very light simmer.
Heat 1 T each olive oil and butter in a sturdy pan with straight sides on medium-high heat and sauté the mushrooms with a pinch of salt to release their liquids and caramelize them, about 5 minutes. Remove from the pan and set aside.
Lower the heat to medium. Add remaining 1 T olive oil and 1 T butter to the pan used to cook the mushrooms. Add the onions and garlic (if using), and gently sauté for 2 minutes, then add the rice. Stir to coat the rice in the oil and butter and gently toast the rice, 2 minutes more - do not brown the soffritto or the rice.
Deglaze the pan with the white wine. Gently stir until fully absorbed before adding stock.
Slowly add simmering stock, 1/2 cup at a time, gently stirring to ensure the stock is fully absorbed before adding more. Continue gradually adding stock and gently stirring until almost all of the stock has been used and the risotto is 90-95% done. This part of the process should take 15-20 minutes.
Stir in remaining 2 T butter and both cheeses.
Crumble goat cheese into the risotto, lightly stir to combine.
Serve immediately. Stir in or top your risotto with the mushrooms when serving. Garnish with a little chopped parsley leaves and more cheese.