My Grandma's Secret meatloaf recipe with oatmeal

Ingredients

• 1.5 lbs (680g) ground beef (80/20 blend recommended)
• 1 cup (90g) rolled oats (not instant)
• 1 cup (240ml) milk (any type, dairy or non-dairy)
• 1 medium onion, finely chopped (about 1 cup)
• 2 cloves garlic, minced
• 1 large egg, lightly beaten
• 1/4 cup (60ml) ketchup
• 1 tablespoon Worcestershire sauce
• 1 teaspoon dried thyme
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1/2 cup (120ml) ketchup
• 2 tablespoons brown sugar, packed
• 1 tablespoon yellow mustard