Preheat your oven to 350°F. Line a 9x13" baking pan with parchment paper.
Use a cheese grater to grate your cauliflower florets. Transfer the shreds to a large skillet and saute for 5 minutes, flipping occasionally. We want the water to evaporate but not brown the vegetable - keep the heat on medium. Transfer the shreds to a cloth to wring out any excess liquids still left in the vegetable.
In a small skillet, add the oil and heat on medium. Add in the garlic and saute for 30 seconds to 1 minute or until fragrant.
In a large bowl, combine the cauliflower, garlic, eggs, dried herbs, onion powder, salt and pepper to taste and 1 cup of the mozzarella cheese. Transfer the mixture to your prepared baking dish and flatten out evenly. Bake for 30 minutes. Remove and flip it over onto another slightly larger baking sheet lined with parchment. Bake in the oven for 10 minutes. Remove and top with the remaining mozzarella and your pepperoni. Broil until the cheese turns golden brown and bubbly.
Notes
You can use frozen cauliflower rice too - just make sure you cook it off as instructed or in your microwave for 8 minutes. And then don't forget to ring it out in your cheesecloth (either way). You should have around 3.5 cups packed cauliflower rice.