Preparation Melt butter in heavy large saucepan over medium heat. Add onion. Cover and cook until golden, stirring occasionally, about 15 minutes. Add rice, porcini, 1 cup porcini soaking liquid, 3 1/2 cups broth and Cognac. Bring to boil. Reduce heat to medium-low; simmer uncovered until rice is tender and mixture is creamy, stirring occasionally and adding broth if dry, about 20 minutes. Season with salt and pepper. Pass cheese separately.
Preparation Melt butter in heavy large saucepan over medium heat. Add onion. Cover and cook until golden, stirring occasionally, about 15 minutes. Add rice, porcini, 1 cup porcini soaking liquid, 3 1/2 cups broth and Cognac. Bring to boil. Reduce heat to medium-low; simmer uncovered until rice is tender and mixture is creamy, stirring occasionally and adding broth if dry, about 20 minutes. Season with salt and pepper. Pass cheese separately.