Roughly dice the onion and sauté in olive oil on medium-low heat and season with salt and pepper.
In the meantime roughly dice the tomatoes. When the onion is translucent add the tomatoes. Allow the mix to simmer for 5 minutes, stirring regularly, then add the balsamic and sugar.
Allow to simmer for a further 10 minutes. Add it to a homemade burger or hot dog.