Preheat oven to 375°F (190°C) and line a small baking sheet or loaf pan with parchment paper.
Finely dice the yellow onion and mince the garlic clove.
In a large mixing bowl, combine the ground beef, egg, almond flour, diced onion, minced garlic, 1 tablespoon of tomato paste, coconut aminos, sea salt, and black pepper.
Use your hands to gently mix the ingredients until just combined, being careful not to overwork the meat.
Shape the mixture into a uniform loaf on the prepared baking sheet.
In a small bowl, whisk together the remaining 1 tablespoon of tomato paste, balsamic vinegar, and maple syrup to create the glaze.
Bake the meatloaf for 25 minutes, then remove from the oven and brush the savory glaze evenly over the top and sides.
Return to the oven and bake for an additional 10-15 minutes, or until the internal temperature reaches 160°F (71°C) and the glaze is bubbly.
Let the meatloaf rest for 5-10 minutes before slicing to ensure it stays juicy.