Open-Faced Garlic Toast Sloppy Joes (Cheesy 30-Minute Dinner)

Ingredients

• 1 tablespoon olive oil
• 1 lb (450 g) ground beef, 85 to 90 percent lean
• 1 small yellow onion, finely diced
• 2 cloves garlic, minced
• 1 1/2 cups (360 ml) marinara or spaghetti sauce
• 1 tablespoon Worcestershire sauce
• 1 tablespoon yellow mustard
• 1 teaspoon brown sugar, optional
• 1 teaspoon Italian seasoning
• 1/2 teaspoon kosher salt, plus more to taste
• 1/4 teaspoon black pepper
• 8 slices frozen garlic Texas toast
• 1 1/2 cups (170 g) shredded mozzarella cheese
• 2 tablespoons chopped fresh parsley