Preheat oven to 375 degrees Fahrenheit.
In a large saucepot over medium heat bring chicken stock and garlic to a simmer for 3 – 5 minutes. Add heavy cream and reduce by one-third.
In a fry pan over medium high heat add 2 tablespoons butter and 2 tablespoons olive oil. Add chantrelles and cook for 1 minute. Season with salt and pepper. Add another tablespoon of butter and continue to cook mushrooms until they are light golden brown.
Coat a casserole dish with a little olive oil. Layer bottom with sole, season with salt, pepper and juice of 1/2 a lemon. On top of fish, add a layer of potato, onion, spinach & chantrelles. Sprinkle with chopped herbs & ladle stock reduction over top. Repeat until all ingredients are used. Top with white wine. Place casserole in oven for 1-11/4 hour.