Meatloaf Sandwiches With Apples Cheddar

Name: Meatloaf Sandwiches With Apples & Cheddar
Ingredients: For the meatloaf:; 1 tablespoon olive oil; 1 medium onion, finel chopped (about 1 cup); 1 celery stalk, finely chopped; 1 medium carrot, finely chopped; 1 teaspoon minced fresh thyme; 1/2 teaspoon fennel seeds; 1/2 teaspoon hot sauce; 2 cloves garlic, minced; 2 teaspoons kosher salt; 1 teaspoon freshly ground black pepper; 1 tablespoon Worcestershire sauce; 2/3 cup ketchup, divided; 2 tablespoons tomato paste; 2 large eggs, lightly beaten; 1/3 cup chopped fresh parsley; 1/2 cup breadcrumbs; 1 1/2 pounds lean ground beef; For the sandwiches:; 4 Arnold®, Brownberry®, or Oroweat® 100% Whole Wheat Sandwich Buns; 3 tablespoons Dijon mustard; 1 medium apple, peeled and thinly sliced or shaved on a mandoline; 8 slices aged cheddar cheese; 4 pieces butter lettuce