Melt the butter in a skillet over medium heat. The pan should look glossy and evenly coated before the mushrooms go in.

Add the finely diced mushrooms and cook them for 10 to 15 minutes. They will first release liquid, then the pan will sound drier and the mushrooms will shrink and turn deep golden brown.

Stir in the onion powder, garlic powder, salt, pepper, and chicken broth, then scrape the skillet with a wooden spoon to lift the browned bits. Cook for 5 minutes, and when everything looks well combined, remove about 1/3 of the mushrooms and set them aside.

Pour in the heavy cream, then blend the soup in the skillet with an immersion blender until mostly smooth. Lower the heat before blending and keep the blender head submerged so the hot liquid stays controlled and the soup thickens without splashing.

Return the reserved mushrooms to the skillet and continue cooking for 15 to 20 minutes. Keep the soup at a gentle simmer, not a hard boil, until it looks velvety and coats the spoon.

Serve the soup, or cool it and transfer it to an airtight container for later. The finished texture should be creamy with some mushroom bits still visible for a more homemade feel.