Shiitake Mushroom And Yukon Gold Potato Gratins With Fresh Herbs Recipe

Ingredients

• 12 sprig fresh italian parsley, stemmed
• 8 sprig thyme, stemmed
• 2 sprig winter savory or rosemary, stemmed
• 2 large cloves garlic, chopped finely
• 2 tablespoon unsalted butter
• 4 tablespoon extra-virgin olive oil
• 1 1/2 pound fresh shiitake mushrooms, stems trimmed, cut into 1/8-inch slices
• 2 large shallots, quartered and sliced finely
• 1/2 teaspoon sea salt
• freshly ground pepper, to taste
• 1 1/2 cup whole milk
• 1/2 cup heavy cream
• 1/4 teaspoon sea salt, or to taste
• 1 pound medium yukon gold potatoes, cut into 1/8-inch slices using a mandoline or the blade attachment of a food processor
• 4 ounce cave-aged gruyère, grated coarsely