Preheat oven to 425°

Combine first 10 ingredients in a large bowl and mix loosely

In a large skillet, melt 1/4 cup butter over medium high heat, and saute mushrooms, once mushrooms have started to brown, deglaze pan with 1/4 cup sherry and summer until liquid is almost gone

mix mushroom mixture into meatloaf, and form into loaf shape on a half sheet pan lined with aluminum foil (makes for each cleanup)

Bake for 30-35 minutes

In a large saucepan, whisk together 2 Tbsp sherry, bourbon, brown sugar, soy sauce, Worcestershire, and brown mustard until smooth, Bring to a simmer over medium-low heat, then remove from the burner, and whisk in the 3/4 cup of unsalted butter one piece at a time. Do not return to the heat.

Serve meatloaf covered with sauce