Combine beef and soy sauce in medium bowl; set aside for 15 minutes.

Heat oil in large Dutch oven over medium-high heat until just smoking.

Add mushrooms and onion; cook, stirring frequently, until onion pieces are brown and dark bits form on pan bottom, 8 to 12 minutes.

Transfer vegetables to bowl.

Add beef and cook, stirring occasionally, until liquid evaporates and meat starts to brown, 6 to 10 minutes.

Add tomato paste and garlic; cook, stirring constantly, until aromatic, about 30 seconds.

Add red wine, scraping bottom of pot with wooden spoon to loosen browned bits, and cook until syrupy, 1 to 2 minutes.

Add beef broth, chicken broth, carrots, celery, bay leaf, and browned mushrooms and onion; bring to boil.

Reduce heat to low, cover, and simmer until vegetables and meat are tender, 25 to 30 minutes.

While soup is simmering, sprinkle gelatin over cold water and let stand.

When soup is finished, turn off heat.

Remove bay leaf.

Add gelatin mixture and stir until completely dissolved.

Stir in parsley; adjust seasonings with salt and pepper.

Serve.