Make sure you give your mushrooms enough room and time to sweat out all their moisture and get properly browned before pouring in the broth. Splashing in dry white wine lifts up all those caramelized, flavor-packed bits stuck to the bottom of the pot, and from there you just let everything simmer away until the mushrooms are completely tender.
The real trick is pureeing only a portion of the batch so you end up with a rich, silky base that still features hearty bites of mushroom throughout. A splash of soy sauce provides that deep, savory umami backbone - just pour it in bit by bit and taste as you go before reaching for extra salt. Standard button mushrooms do a fantastic job here, though swapping in cremini gives you an even earthier hit. Best of all, you get plenty of luxurious body without ever needing heavy cream.