Clean mushrooms, mirepoix, and pumpkin, and use scraps to make a stock with a bay leaf. Bring to a low simmer for 30 min, allow to rest 30 min before using
Toast saffron over low heat quickly turning until dry enough to pulverize to powder
Use 1/2 butter to sautée mirepoix and pumpkin until softened, add bay leaf rice, turn frequently for 5 min, add 1/2 stock, and continue stirring.
Add saffron, and continue stirring.
When the stock has absorbed, add a healthy splash of sherry or vermouth, and add the remaining stock, stirring constantly.
Season with salt/pepper, and add the remaining butter.
Turn down to medium heat, stir constantly until stock is mostly absorbed turn off. Permit to rest before serving. Should be creamy, and slightly wet, you should add fresh thyme, mascarpone, or créme fraîche before serving.
Grate over nice dry cheese like Manchego or Pecorino. Pair with dry, floral Rueda, Viura, or Oloroso Sherry.