Green Mashed Potatoes

Name: Green Mashed Potatoes
Ingredients: 2 pounds russet potatoes (about 3 large or 5 medium-sized potatoes), peeled and cut into 2-inch chunks; Salt; 3 sprigs thyme (or a couple teaspoons dried thyme in a small bouquet garni bag or tied up with cheesecloth); 1 bunch fresh parsley , leaves chopped (about 1 cup); 3 green onions (scallions), white and green parts chopped (about 1/2 cup); 1/2 cup milk , divided; 1/4 cup cream; 3 tablespoons butter , more to taste; 1 teaspoon freshly ground black pepper