Grease the slow cooker insert lightly with oil, slice sausage into chunks, and add to the slow cooker with diced potatoes and tomatoes.

In a medium mixing bowl, whisk together chicken broth, minced garlic, and Hollandaise sauce until smooth.

Pour the broth mixture over the sausage and potato layers and stir gently to combine.

Cover the slow cooker and cook on high for 4 hours or low for 8 hours.

Ladle the soup into bowls and top with scrambled eggs and sautéed mushrooms.