Preheat the oven to 375 degrees and lightly grease a loaf pan.
In a large bowl, combine the ground beef, breadcrumbs, 1/4 cup apple cider, egg, onion, garlic, 1 tablespoon rosemary, salt, and pepper. Mix with your hands until the ingredients are evenly distributed.
Transfer the mixture to the prepared loaf pan and shape it into a firm loaf.
In a small bowl, stir together the remaining 1/3 cup apple cider, brown sugar, and 1 teaspoon rosemary until the sugar mostly dissolves.
Pour half the glaze over the top of the meatloaf. Bake for 30 minutes.
Remove the pan from the oven, pour the remaining glaze over the loaf, and return it to the oven for another 20 to 25 minutes until the internal temperature reaches 160 degrees.
Let the meatloaf rest for 5 minutes before slicing.