Preheat the oven to 375 degrees F.

Toss the bread cubes with the olive oil and 2 teaspoons of salt and 1 teaspoon of pepper. Divide the cubes between two baking sheets and toast in the oven for 20 minutes or until golden brown. Remove from the oven and set aside.

In a large Dutch-oven over medium heat cook the bacon until it begins to crisp around the edges, about 4 to 5 minutes. Add 4 tablespoons of the butter, onions, fennel and celery and continue to cook, stirring occasionally, until the vegetables are wilted and translucent, about 20 minutes.

Meanwhile, in a large mixing bowl combine the eggs, stock, heavy cream, sour cherries, hazelnuts and remaining salt and pepper and mix well. Add the bread cubes and stir until all of the bread is well coated.

Transfer the onion and bacon mixture to the bowl with the eggs and stock and mix well.

Increase the heat to medium-high and add the apples and thyme. Cook the apples, stirring, until golden brown, about 5 minutes. Transfer the apples to the bowl with the bread and mix well.

Grease a 9 by 13-inch baking dish with the remaining 1 tablespoon of butter. Transfer the dressing to the baking dish and cover with aluminum foil. Bake covered for 30 minutes and uncovered for another 30 minutes.

Serve hot.