1. Preheat the oven to 375°F. Cut the bread into 1-inch cubes and lay in a single layer on a baking sheet. Bake until bread is toasted, about 15 minutes. Transfer to a very large mixing bowl and set aside.
   
   
2. Warm the olive oil and 4 tablespoons of butter in a very large, heavy skillet over medium-high heat. Once the butter is melted, add the onions, mushrooms and celery. Season generously with salt and pepper and sauté, stirring occasionally, until soft, about 8 minutes. Add the garlic and thyme and cook for another minute. Add 2 cups of broth and cook until the mixture thickens, about 10 minutes. Carefully transfer to the mixing bowl with the bread.
   
   
3. To the mixing bowl, add the remaining 2 cups broth, heavy cream, eggs, 1 tablespoon salt and 2 teaspoons pepper. Stir to combine. Transfer to a large 13"x8" buttered baking dish and spread into an even layer. Cut the remaining 2 tablespoons of butter into small pieces and dot the top of the stuffing. Cover with aluminum foil and bake for an hour. Remove foil and bake for another 60–75 minutes or until stuffing is set. Serve warm from the oven.

Notes:

This is a great dish to prepare the day before. You can make this all the way up to baking and then keep in the refrigerator for up to 24 hours. Let stuffing sit on the counter for an hour before baking.

Choose a bread that is crusty such as peasant bread, ciabatta, French or Italian.

The step of toasting the bread is important. The drier the bread, the more flavour it will absorb.

Cremini, oyster, portobello and shiitake are all great wild mushroom selections and hugely flavourful. But use any mushroom varieties you can find. Wild mushrooms can be pricey, and honestly, this is just as delicious with brown mushrooms.

The stuffing (when covered) will keep its heat for a while, so you can plan to take it out of the oven about an hour before dinner service.