Step 1

Melt the butter in a sauce pan over medium high heat. Add the mushrooms and sweat, stirring occasionally, about 5 minutes. Add the garlic and saute, stirring often, about 15 minutes until mushrooms are browned and all liquid has evaporated.

Step 2

Preheat the broiler. Spread the mustard evenly on one side of each piece of bread. Top each slice with a sprinkle of cheese. Evenly top with the mushrooms and then top each with another generous sprinkle of cheese. Broil until the cheese is melted and starting to brown, about 2 minutes.*

Step 3

To serve, sprinkle with fresh thyme and season with salt and pepper.