Finely dice the onions, finely chop the garlic, divide the zucchini into not too coarse cubes.
Fry the onions and garlic in a little olive oil. Add the tartar and brown all over. Add the zucchini cubes and sauté briefly. Top up with bouillon as desired. Simmer on a low flame for about 10-12 minutes until the zucchini is done but not mushy.
In the meantime, chop the parsley.
Take the saucepan off the stove, stir in the yoghurt, season with salt, possibly grained beef broth, lots of pepper and lemon juice to taste. Add the parsley.
Tip: You can also make this soup without yogurt. Of course, you can also use ground beef instead of tartare.