Step 1

Bring stock to a boil over medium high heat in a medium saucepan. Remove from heat and add in porcini mushrooms. Let steep until mushrooms are tender, about 15 minutes. Drain mushrooms, reserving stock. Roughly chop mushrooms.

Step 2

Melt butter in medium saucepan over medium heat. When foaming subsides, add porcini, cremini, and shiitake mushrooms and cook, stirring occasionally, until browned, about 10 minutes.

Step 3

Add flour and cook, stirring constantly, for 1 minute.

Step 4

Slowly whisk in reserved stock. Bring to a boil, reduce to a simmer, and cook until gravy has thickened and reduced to 3 cups, 10 to 15 minutes. Stir in sherry and continue to cook until warmed through, about 1 minute. Season with salt and pepper to taste. Serve immediately or store in an airtight container in refrigerator for up to one week, reheating over medium-low heat before serving.