Shiitake Mushroom Frittata with Pecorino Romano for Two | America's Test Kitchen

Ingredients

• 6 large eggs
• 2 tablespoons whole milk
• Salt and pepper
• 1 1/2 teaspoons extra-virgin olive oil
• 8 ounces shiitake mushrooms , stemmed and cut into 1/2-inch pieces
• 1 tablespoon water
• 1 scallion , white part minced, green part sliced thin
• 1 1/2 teaspoons sherry vinegar
• 3/4 teaspoon minced fresh thyme
• 1 1/2 ounces Pecorino Romano , shredded (1/2 cup)