Preheat your oven to 375°F and line a small loaf pan or baking sheet with parchment paper.
Finely dice the yellow onion and mince the garlic clove.
In a medium mixing bowl, combine the lean ground beef, egg, almond flour, onion, garlic, sea salt, black pepper, and dried thyme.
Mix the ingredients gently by hand until just incorporated, ensuring you do not overwork the meat to maintain a tender texture.
Shape the mixture into a uniform loaf and place it on the prepared baking surface.
In a small bowl, whisk together the tomato paste, apple cider vinegar, and maple syrup to create the glaze.
Brush the glaze evenly over the top and sides of the meatloaf.
Bake for 25 to 30 minutes, or until the internal temperature reaches 160°F.
Remove from the oven and let the meatloaf rest for 5 minutes before slicing to ensure it remains juicy.