In a large Dutch oven, combine the cauliflower and pizza sauce and stir well to coat. Bring the sauce to a boil over medium-high heat and, once bubbling, lower the heat to a simmer and cover the pot to let the cauliflower cook until fork-tender, about 15 minutes.
While cauliflower is cooking, grab a skillet and sauté the turkey until cooked, drain and set aside.
Preheat the oven to 350°F. In a medium bowl, beat together the eggs, grated cheese, and salt. Set aside. After the cauliflower is tender, stir in the spinach and simmer to cook off any excess moisture in the pot, to ensure that the final result isn’t watery. Remove the pot from the heat and stir in the turkey as well as the egg and cheese mixture. Top with the shredded cheese.
Bake for 30 minutes, until the eggs have set and the cheese is bubbly on top. Allow the dish to cool for 10 minutes, then serve warm. Store leftovers in an airtight container in the refrigerator for up to 5 days.