Preheat the oven to 350°F (180°C) and line a baking pan with baking paper.
In a large mixing bowl, combine the minced beef with the parmesan cheese, eggs, onion, garlic, flaxseed, salt, paprika and parsley.
Let the mixture rest for 5-10 minutes so that the flaxseed can soak up all the extra liquids.
Transfer on the pan and shape into a loaf.
Mix the tomato paste with the balsamic vinegar and season with a pinch of salt and paprika. Brush the top of the meatloaf with the mixture.
Bake in the oven, uncovered for 60 minutes until cooked through.
Let it rest for around 15 minutes before slicing and serving.