While the meatloaf bakes, whisk together the ketchup, apple cider vinegar, maple syrup, brown sugar, dijon mustard, and hot sauce (if using). This tangy glaze is basically my go-to meatloaf sauce recipe: sweet, sharp, and glossy.
After 40 minutes of baking, brush about half the glaze over the top and sides. Return to the oven and bake for 15 minutes.
Brush on the remaining glaze and bake for 5 minutes more. The glaze should look shiny and a little sticky at the edges.
Check doneness with an instant-read thermometer in the center of the loaf; it should read 160°F. If it's not there yet, keep baking until it hits temperature.
Rest the meatloaf on the pan for 10 minutes before slicing. This is where the juices settle back in, so you get clean slices instead of a crumble-and-weep situation.