Cottage Pie with Potato Tots

Name: Cottage Pie with Potato Tots
Ingredients: 4 cups (18 ounces) frozen potato tots; 2 tablespoons extra-virgin olive oil; 4 large scallions, thinly sliced (dark green parts separated); 1 carrot, diced; Kosher salt and freshly ground pepper; 2 cloves garlic, minced; 1/2 teaspoon dried thyme; 1 pound lean ground beef; 2 tablespoons tomato paste; 5 teaspoons all-purpose flour; 1 3/4 cups beef broth, warmed; 1 cup frozen cut green beans