Slice the mushrooms: Cut them into thin, even slices so they cook quickly and evenly, about 1/4-inch thick.
Slice the avocado: Cut it lengthwise around the pit, remove the stone, scoop out the flesh, and slice into thin wedges.
Prepare the tomato and onion: Slice your tomato into 2 clean pieces and finely dice the red onion into small pieces.
Toast the bread: Toast your whole-grain slices until golden and crispy.
Sauté the mushrooms: Heat 1/2 tablespoon of olive oil in a skillet over medium-high heat, add the mushroom slices with a pinch of salt, and cook for 4-5 minutes until golden and tender.
Cook the egg: In the same skillet, add the remaining 1/2 tablespoon olive oil and crack your egg into the pan, cooking it to your preference (fried eggs take 3-4 minutes for runny yolks, longer if you prefer them set).
Season everything: Season both the mushrooms and egg with salt and black pepper as they cook.
Spread the hummus: Take each slice of toasted bread and spread 1 tablespoon of hummus evenly across the surface.
Layer the vegetables: Arrange the spinach on top of the hummus, then layer on the tomato slices, avocado slices, and sautéed mushrooms.
Top with the egg: Carefully place your cooked egg on top of each toast slice.
Garnish and serve: Sprinkle the diced red onion over the top, add a pinch of fresh parsley, and finish with a light dusting of salt and pepper. Serve immediately while the toast is still warm.