Prepare Mushrooms: Clean 400g mixed mushrooms (porcini, cremini, shiitake) with damp cloth (do not wash). Slice 300g into 1/4-inch slices, finely chop 100g for flavor base. If using dried porcini (20g), soak in 2 cups hot water 30 minutes, reserve liquid, chop rehydrated mushrooms.
Make Mushroom Stock: In saucepan, combine 1.5L vegetable or chicken stock, mushroom soaking liquid (strained through coffee filter), 1 smashed garlic clove, 1 sprig thyme. Heat to simmer, keep warm.
Sauté Mushrooms: Heat 2 tbsp olive oil + 1 tbsp butter in large skillet over medium-high. Add sliced mushrooms, cook 8-10 minutes until browned and liquid evaporates. Season with salt, pepper, 1 tsp chopped thyme. Remove half for garnish.
Start Risotto Base: In heavy-bottomed pot, melt 3 tbsp butter over medium. Add 1 finely chopped shallot, cook 3 minutes until soft. Add 400g Carnaroli rice, toast 2 minutes until translucent edges.
Deglaze: Add 1/2 cup dry white wine, stir until absorbed.
Begin Adding Liquid: Add 1 ladle (about 1/2 cup) hot mushroom stock, stir constantly until absorbed. Continue adding stock ladle by ladle, maintaining gentle simmer.
Add Mushrooms: After 10 minutes, stir in chopped mushrooms and half of sautéed sliced mushrooms.
Continue Cooking: Continue adding stock and stirring for another 8-10 minutes until rice is al dente with creamy consistency.
Final Touch: Remove from heat, stir in 2 tbsp cold butter, 1/2 cup grated Parmigiano-Reggiano, 2 tbsp chopped parsley. Cover, rest 2 minutes.
Serve: Divide among bowls, top with reserved sautéed mushrooms, extra Parmigiano, drizzle of truffle oil (optional).

