Heat a Dutch oven over medium-high heat. Add sausage and break it up with a wooden spoon. Add ground beef and cook, with sausage, breaking it up with a wooden spoon or potato masher, until browned and crumbled.

Turn heat to high. Add onions and celery and cook until onion begins to soften, about 1 minute. Stir in carrots and cook for 2 minutes. Add garlic, soup mix, salt, and pepper and cook until fragrant, about 2 minutes.

Stir in broth, tomatoes, water, and bay leaf and bring mixture to a boil, stirring occasionally. Add potatoes and green beans and cook until mixture returns to a boil. Reduce heat slightly and simmer, covered until vegetables are tender.

Meanwhile, cut mushrooms in half vertically. Place mushrooms, flat side down on a work surface and use a straw to poke 2 holes for skeleton “eyes.” Make a third hole for a nose or use a paring knife to make 2 small slits for a nose.

Add mushrooms to the pot and cook until just tender, about 10 minutes longer. Season to taste with salt and pepper if desired and serve with fresh chopped parsley.