Mustard Herb Chicken Cutlets and Garlic Spinach

Name: Mustard Herb Chicken Cutlets and Garlic Spinach
Ingredients: Four 6-ounce boneless, skinless chicken breasts; Kosher salt and freshly ground black pepper; 4 tablespoons salted butter; 1 tablespoon olive oil; 3 cloves garlic, minced; 1 cup dry white wine; 2 heaping tablespoons grainy mustard; 1 cup low-sodium chicken broth; 1/2 cup chopped mixed fresh herbs, such as dill, parsley or chives, plus more for garnish; Garlic Spinach, recipe follows; 2 tablespoons olive oil; 2 garlic cloves, minced; Two 10-ounce packages baby spinach leaves; 1/2 teaspoon kosher salt; 1/4 teaspoon freshly ground black pepper; Juice of 1/2 lemon