Reserve some sage leaves and several mushrooms to decorate and add the beans and a cup of the mushroom water. Cook covered over low heat for about five minutes.
In a mortar, chop the walnuts with the other half of the sage leaves and a pinch of salt. Add the mince to the casserole, stir well and cook for 5 minutes. Before serving, season, taste and rectify if necessary.
To serve, plate the four portions and decorate the plates with the reserved black trumpets and sage leaves.
Culinary Tips
If you find fresh Black Trumpets, use 300 grams of mushrooms and replace the soaking water with vegetable broth. The style of the dish is that of a wet but not too soupy bean stew. If you prefer, use twice as much soaking water / broth to serve a more soupy dish. If you cook the beans at home, use the remaining soaking water from the mushrooms to cook them. The result is even more aromatic.
Recipe by The Quotidian Cook at https://www.thequotidiancook.com/en/black-trumpets-and-beans-stew/