Preheat your oven to 425°F (220°C).
Rice the cauliflower by processing it until it reaches a fine, rice-like texture. Transfer it to a microwave-safe bowl and microwave for 4-5 minutes until softened. Allow to cool slightly.
In a bowl, combine the riced cauliflower, 1 beaten egg, and grated Parmesan cheese. Mix until well combined. Transfer the mixture onto a baking sheet lined with parchment paper and press it into a thin, even circle to form the crust.
Bake the cauliflower crust in the preheated oven for 15-20 minutes until it starts to firm up and turn slightly golden.
While the crust is baking, toss the red bell pepper, zucchini, red onion, and spinach with a little salt and pepper. Spread them out on a separate baking sheet and roast in the oven for about 10 minutes, until tender.
Prepare your crispy chicken: if not already pre-cooked, season your chicken breast with herbs and a dash of salt, then bake it until cooked through and slightly crispy, or use pre-cooked crispy chicken strips.
Once the crust is ready, spread a thin layer of tomato sauce over it. Arrange the roasted vegetables evenly on top.
Slice the crispy chicken into strips and distribute them over the vegetables. Sprinkle the part-skim mozzarella cheese over the top.
Return the pizza to the oven for an additional 5-7 minutes to allow the cheese to melt and the flavors to meld.
Remove the pizza from the oven, let it cool for a few minutes, slice, and serve warm.