Root Vegetable Skillet Pot Pie

Name: Root Vegetable Skillet Pot Pie
Ingredients: 1 pie crust; 3 tablespoons salted butter; 1/2 large yellow onion , diced; 2 large carrots , diced; 1 large sweet potato (1 1/2 cups), peeled and diced; 1 large R usset potato (1 1/2 cups), peeled and diced; 2 small sprigs (1/2 tablespoon) fresh rosemary , minced; 1/2 teaspoon dried rubbed sage; 1 teaspoon kosher salt; 1/8 teaspoon ground black pepper; 2 tablespoons garlic , thinly sliced; 3 tablespoons all-purpose flour; 1 1/2 cups no-chicken broth or vegetable broth; 1 cup whole milk; 1 cup frozen peas