Preheat oven to 350°F. Line a baking sheet with foil (or lightly grease a 9x5-inch loaf pan).
In a small bowl, whisk together all glaze ingredients (applesauce, brown sugar, vinegar, mustard). Set aside.
In a large bowl, combine ground meat, applesauce, breadcrumbs, eggs, onion, Worcestershire sauce, mustard, salt, pepper, and thyme. Mix gently with your hands until just combined. Do not overwork.
Shape the mixture into a loaf on the prepared baking sheet (about 9 inches long and 5 inches wide), or press into the loaf pan.
Spread half of the applesauce glaze over the top of the loaf.
Bake for 45 minutes. Remove from oven and spread the remaining glaze over the top.
Bake for another 15 minutes until the internal temperature reaches 160°F and the glaze is caramelized.
Let the meatloaf rest for 10 minutes before slicing and serving.
Notes
Applesauce: Use unsweetened for best results. If using sweetened, omit the brown sugar from the glaze.
Meat blend: A beef and pork blend adds extra juiciness. All beef works too, just use 80/20 for best texture.
Don't overwork: Mix gently with your hands until just combined. Over-mixing makes the loaf dense.
Resting: Let it rest 10 minutes before slicing so the juices redistribute.
Storage: Refrigerate for 3-4 days, or freeze individual slices for up to 3 months.
Slow cooker: Shape loaf, place on foil in crockpot, top with glaze. Cook on low for 4-6 hours.