Process everything, except tomato paste and soy sauce, in food processor, scraping down sides of bowl frequently, until paste is as fine as possible, about 3 to 4 minutes.
Add tomato paste and process for one minute, scraping down sides of bowl every 20 seconds.
Add soy sauce and continue to process one minute longer.
Transfer mixture to airtight container and tap firmly on counter to remove any air bubbles. Press small piece of parchment paper against surface of mixture and cover.
Freeze up to 6 months.
Use 1 tbl to one cup boiling water to make broth. Strain if you desire a particle-free broth. The salt content of the mixture will keep it from freezing so that you can scoop it straight from the container.