Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a food processor, pulse the cauliflower florets until they resemble rice or fine crumbs. Transfer to a clean kitchen towel and squeeze out as much moisture as possible.
In a large bowl, combine the cauliflower, egg, mozzarella cheese, almond flour, garlic powder, onion powder, salt, and black pepper. Mix until well combined.
Spread the cauliflower mixture onto the prepared baking sheet, forming it into rectangular 'toast' shapes about 1/4 inch thick.
Bake in the preheated oven for 25-30 minutes, or until golden brown and firm to the touch.
While the toast is baking, mash the avocado in a small bowl and season with salt and pepper to taste.
Once the cauliflower toast is done, remove it from the oven and let it cool slightly. Spread the mashed avocado on top of each toast.
Sprinkle crumbled feta cheese over the avocado and drizzle with olive oil. Garnish with fresh herbs before serving.