from Veganomicon

3 T olive oil
1 c diced yellow onion
3 cloves garlic
1 t dried thyme
1 t dried terragon
3/4 t salt
freshly ground black pepper
1 lb cremini mushrooms, chopped
1 cup lightly toasted walnuts
3/4 cup cooked cannelini beans
1 t balsamic vinegar
up to 1/4 c cold veggie broth (note: I didn't need any)

Heat 2 T of the oil in a large skillet over medium heat. Add the onions and sauté for 3 to 5 minutes until translucent, then add the garlic, thyme, tarragon, salt, and pepper, and cook for another few seconds. Next, add the mushies and cook for 7-10 minutes until they are very soft, lowering the heat if necessary to prevent burning.

While that's cooking, place the nuts in a food processor or blender and process until very fine.

Add the mushroom mixture to the processor, along with the vinegar, beans, and remaining T of oil. Process until smooth, adding the veggie broth 1 T at a time as needed. Continue to puree until you've got a smooth, thick, spreadable paste. Scrape mixture into an airtight container and chill for at least an hour before serving to allow the flavors to meld.