Mushroom and Leek Bread Pudding

INGREDIENTS

2 oz

Pancetta, small

1/3 cup

Flat-leaf parsley, fresh

4 cups

Leeks

1 tbsp

Tarragon, fresh leaves

Eggs, large

1 cup

Chicken stock

Kosher salt and freshly ground black pepper

2 tbsp

Olive oil, good

6 cups

Bread

1 tbsp

Butter, unsalted

1 1/2 cups

Gruyere cheese, grated

1 1/2 cups

Heavy cream

1/4 cup

Sherry, medium or dry

1 1/2 pounds cremini mushrooms, stems trimmed and 1/4-inch-sliced