For the pizza: Preheat the oven to 425 degrees F. Line a rimmed baking sheet with parchment paper.
Pulse the cauliflower florets in a food processor to a fine snowy powder (you should have about 2 1/2 cups). Transfer the processed cauliflower to a microwave-safe bowl and cover. Microwave until soft, 4 to 6 minutes. Transfer to a clean, dry kitchen towel and allow to cool.
When cool enough to handle, wrap the cauliflower in the towel and wring out as much moisture as possible, transferring to a second towel if necessary. In a large bowl, stir together the cauliflower, Parmesan, Italian seasoning, salt, egg and 1 cup of the mozzarella until well combined. Transfer to the prepared baking sheet and press into a 10-inch round. Bake until golden, 10 to 15 minutes.
Remove the crust from the oven and top with the Spicy Pizza Sauce and remaining 1 cup mozzarella. Bake until the cheese is melted and bubbly, 10 minutes more. Garnish with fresh basil leaves just before serving.
For the salad: Meanwhile, add the greens to a large bowl. Whisk together the olive oil, baslsamic and salt and pepper to taste in a measuring cup. Pour over the greens and toss. Top with Parmesan shavings.
Heat a pan over medium-high heat until hot. Add a tablespoon or so of olive oil, throw in the garlic and chopped onions and give them a stir. Cook until the onions are soft, 4 to 5 minutes. Add the chicken broth, whisking to deglaze the bottom of the pan. Cook until the liquid reduces by half. Add the crushed tomatoes and stir to combine. Add the brown sugar, red pepper flakes and salt and pepper to taste and stir. Bring to a simmer, reduce the heat to low and simmer for 30 minutes. Let cool, then puree the sauce.