Red Lobster New England Clam Chowder

Name: Red Lobster New England Clam Chowder
Ingredients: 2 cups Russet potatoes (peeled and cubed); ½ cup butter; 2 tablespoons diced green onions (white part only); ¼ cup all-purpose flour; 2 cans (6.5 ounces each minced clams (reserve juice)); 1 teaspoon salt (or to taste); 16 ounces half and half; ½ cup whole milk; 1 teaspoon minced garlic; 1 cup diced onions; ½ cup diced celery; ½ cup diced leeks; 1 teaspoon dried thyme; 1 bay leaf; 1 cup heavy cream; Fresh parsley for garnish (optional)