Cabbage Steak Marsala

Name: Cabbage Steak Marsala
Ingredients: 1 small head green cabbage ( 2 lbs. ); 3 tablespoons extra-virgin olive oil , divided; 1/2 teaspoon garlic powder; 1 1/2 teaspoons dried thyme , divided; 1/2 teaspoon ground pepper , divided; 1 ( 8-ounce) package sliced cremini mushrooms; 1/4 cup finely chopped shallot; 2 teaspoons minced garlic; 1/2 cup Marsala; 1 cup lower-sodium vegetable broth; 1 tablespoon cornstarch; 3 tablespoons unsalted butter , cut into pieces; 1/4 teaspoon salt; 1 tablespoon chopped fresh flat-leaf parsley