Mushroom and Leek Bread Pudding

I brought this bread pudding in for a potluck at work this week and it was a huge hit with everyone!  It is a nice mixture of creamy, crunchy and savory.  I added another 1/8 cup of cream and 1/2 cup of chicken stock to the recipe because I like a really moist bread pudding and I knew that I would be reheating it in the oven at work so I didn't want it to dry out.

6 cups bread cubes from a rustic country loaf
2 tbsp olive oil
1 tbsp unsalted butter
4 oz pancetta, diced
4 cups leeks, sliced (white and light green parts only)
1 1/2 lb cremini mushrooms, stems trimmed and 1/4 inch sliced
1 tbsp chopped tarragon
1/4 cup medium or dry sherry
1/3 cup fresh flat-leaf parsley, chopped
4 eggs
1 1/2 cups heavy cream
1 1/2 cups chicken stock
1 1/2 cups grated Gruyere cheese
Salt and pepper

Preheat the oven to 350 degrees.  Spread the bread cubes on a cookie sheet and bake for ~10-15 minutes, until lightly browned.  Set aside.

Meanwhile, heat the oil and butter and oil in a large saute pan over medium heat.  Add the pancetta and cook for 5 minutes, until starting to brown. Stir in the leeks and cook over medium heat for 8-10 minutes, until the leeks are tender.  Stir in the mushrooms, tarragon, sherry, 1 tbsp salt and 1 1/2 tbsp pepper and cook for 10 or 12 minutes, until most of the liquid evaporates, stirring occasionally.  Off the heat, stir in the parsley. 

In a large mixing bowl, whisk together the eggs, cream, chicken stock and 1 cup of the Gruyere.  Add the bread cubes and mushroom mixture, stirring well to combine.  Set aside at room temperature for 30 minutes to allow the bread to absorb the liquid.  Stir well and pour into a 2 1/2 - 3 1/2 gratin dish.  Sprinkle with the remaining 1/2 cup Gruyere and bake for 45 minutes until the top is browned and the custard has set.  Serve hot.