Make the flax egg 

Pulse the walnuts, brazil nuts and cashews.

Cook onions and garlic in a deep skillet over medium heat.

Add the mushrooms and cook until softened,  about 10 minutes.

Add the nutritional yeast, tamari, rosemary, thyme, sage, oregano, and salt.

Add mushroom medley to the food processor with the nuts. Pulse to combine.

Add back to the skillet with chia eggs, rice and tahini. Mix well. 

Line a loaf pan with parchment paper and scoop in the nut roast mixture. 

Bake at 350F/175C until lightly golden, about 50 minutes

Make the optional mushroom topping.

Let the loaf cool for 10 minutes, then remove it from the pan.