Step 1

Bring stock to a simmer in a medium pot over medium heat. Reduce heat to low. Cover and keep warm.

Step 2

Meanwhile, melt 3 tablespoons butter in a large pot over medium heat until it begins to foam. Add onion. Sauté, stirring occasionally, until onion is soft and translucent and just beginning to turn golden, about 5 minutes.

Step 3

Add mushrooms; cook, stirring occasionally, until soft, and any liquid released has evaporated, 5-7 minutes.

Step 4

Add rice; stir to coat. Add 1/2 cup warm stock and stir constantly until liquid is absorbed. Continue adding stock by 1/2-cupfuls, stirring constantly, until rice is tender but still firm to the bite, about 20 minutes. Add leftover turkey meat, if using; stir to combine and to warm through, adding a little stock or water if necessary to keep mixture creamy, about 3 minutes.

Step 5

Stir Parmesan and remaining 1 tablespoon butter into risotto. Season to taste with salt and pepper. Divide among warm bowls. Garnish with chopped parsley.