Help me recreate a dish

[The empressof all]

Years ago SO and I ate at a wonderful French restaurant which unfortunately is no longer in business. We had a wonderful mushroom terrine which SO still talks about to this day. It was a loaf of deep rich mushroom flavors, thick with a meat like consistency. It was served at room temperature.

I have tried to recreate this dish on a number of occasions with very limited success. My best attempt used a duxelle made with porcini and slices of portebellos, layered with demiglace. I used a loaf pan and cooked gently with a weight on top. Still, something was not right.

I have googled and searched but have found no recipe. Has anyone ever had anything like this?

Ideas.