In a medium saucepan, bring broth to a simmer. Cover to keep warm.
Meanwhile, in a larger, heavy sauce pan, sauté mushrooms in 2 tbs butter over medium heat. Season with cumin, nutmeg, and soy sauce. Cook until they've begin to shrink and have browned, about 5 minutes.
Add the thinly sliced leeks. Sauté until soft, stirring often, about 4-5 minutes.
Add rice to pan and cook for 1-2 minutes, stirring constantly.
Add wine to pan and continue to stir until it has been absorbed, about 2 minutes.
Add 1/2 cup warm broth to pan and stir until it has been absorbed. Repeat this process, adding broth 1/2 cup at a time until rice is tender but al dente and the sauce is creamy. The whole process will take about 20-25 minutes.
Stir in the remaining 1 tbs butter, parsley, and Parmesan. Season to taste with salt and pepper, if desired.
Serve, garnished with parsley and Parmesan, and enjoy.