Adjust rack to middle position and preheat oven to 400 degrees. Wash and dry all produce. Bring 4 cups water (7 cups for 4 servings) and stock concentrates to a boil in a medium pot. Once boiling, reduce heat to low. Trim and thinly slice scallions, separating whites from greens. Trim mushrooms, then cut into about ¼-inch-thick slices.

Heat a drizzle of olive oil in a large pan over medium heat. Add scallion whites and mushrooms and cook, stirring, until softened, 1-2 minutes. Add rice and cook, stirring, until translucent, 1-2 minutes. Add stock ½ cup at a time, stirring after each addition. Allow rice to absorb most of the stock before adding more. Continue until al dente and creamy, 30-35 minutes.

Pat chicken dry with a paper towels. Lay two slices of prosciutto beside each other on a flat surface. Tightly roll prosciutto around chicken. Repeat with another two slices of prosciutto and other chicken breast (you may have some prosciutto left over; use the rest as you like).

Heat a drizzle of olive oil in another large pan over medium-high heat. Add wrapped chicken and sear until browned, about 2 minutes per side. Transfer seared chicken to a lightly oiled baking sheet. Place in oven and roast until chicken is cooked through, about 15 minutes. Let rest a few minutes, then slice crosswise.

Quarter lemon. Stir garlic herb butter, half the Parmesan, a squeeze of lemon juice, and any juices released by chicken into risotto. Season with salt, pepper, or more lemon juice (to taste).

Slice chicken crosswise. Divide risotto between plates and sprinkle with scallion greens and remaining Parmesan. Top with chicken. Drizzle with truffle oil (to taste). Serve with any remaining lemon wedges on the side for squeezing over.