Peel the onion and cut into fine strips.
Clean the mushrooms (do not wash) and also cut into strips.
Fry both in some oil until the onions are translucent and the mushrooms are soft.
Then add a little vegan butter, as well as the sugar and the carrot in large slices (peeling not necessary, but removing the stalk).
Also add the thyme, tomato paste and let the roasted aromas develop while stirring. Everything can turn a little darker (but don't burn, so stir diligently). This may take several minutes.
Now deglaze with the broth and red wine, but also the bay leaf, allspice corns, juniper berries, the soy sauce, the red wine vinegar and the mustard are added.
Mix everything well and continue to simmer with the pot open.
This can take another 15 minutes. Stir every now and then.
The aromas unfold slowly and you can add a little salt.
Take the sprigs of thyme, juniper berries, allspice berries and bay leaf out of the sauce and put everything in another container for pureeing. Puree the sauce very finely with a high-performance blender or a hand blender.
If you like it particularly creamy, you can rub the pureed sauce through a fine sieve.
Now put the obtained sauce back into the pot and bring to the boil again on the stove. Then check the consistency and add a little liquid if necessary. Plant-based cream would also be conceivable. If it seems too thin, let it reduce a little further without the lid. This also gives the sauce a slightly stronger taste.