Preheat oven to 360 degrees F. Grease a loaf pan with 1 tablespoon of olive oil.
In a pan over medium heat, add remaining tablespoon of oil. Sauté mushrooms, onion and celery for 5-7 minutes until soft.
In a food processor, combine all ingredients, including sautéed mushroom mixture, until well combined but still chunky. Taste and adjust seasonings as necessary.
Press into prepared loaf pan and bake for about 1 hour and 10 minutes.