Bangers and Mash with onion gravy

Name: Bangers and Mash with onion gravy
Prep time: 30 min
Cook time: 30 min
Total time: 1 h
Cuisine: British
Ingredients: 8 medium starchy potatoes, (peeled and halved); 8 tablespoons unsalted butter; ½ cup milk or light cream; 6-8 banger sausages ((pork, lamb or beef)); 2 teaspoons vegetable oil, (divided); 1 large onion, (halved and sliced thin); 1 large garlic clove, (minced); 1 teaspoon tomato paste; 1 teaspoon fresh thyme leaves, (or ¼ teaspoon dried); 3 tablespoons all-purpose flour; 1 (14.5-ounce) can low sodium beef broth; 1 tablespoon Worcestershire sauce; ½ teaspoon salt; 1 teaspoon pepper; 1 tablespoon fresh chopped parsley leaves