Heat the olive oil in a large skillet over medium high heat. Add the chicken sausage with the casings removed and spread it out across the pan. Let it cook completely undisturbed for 3 to 4 minutes until a deep golden brown sear develops on the bottom. Do not stir it. That sear is where the flavor lives.

Break the sausage into crumbles and add the diced onion. Cook for 2 to 3 minutes until the onion softens and becomes translucent. Add the crushed garlic and cook for 30 seconds stirring constantly so it does not burn.

Add the Italian seasoning, garlic powder, onion powder, red pepper flakes, paprika, and salt. Stir to coat the sausage and onion mixture evenly in the spices.

Pour in the marinara sauce and stir to combine. Let it simmer over medium low heat for 3 to 4 minutes until the sauce has thickened slightly and the flavors have come together. Taste and adjust salt and red pepper flakes as needed.

Spoon a thin layer of the meat sauce across the bottom of a large baking dish. This prevents the cauliflower from sticking and ensures the bottom of each steak stays moist and flavored during the bake.

Scatter the shredded mozzarella evenly over the top then finish with the freshly grated Parmigiano Reggiano. Cover the baking dish tightly with aluminum foil. Bake at 400F for 40 minutes until the cauliflower is fork tender all the way through. To check, insert a knife or skewer into the thickest part of a steak. It should slide through with no resistance.

Use a large spatula to lift each cauliflower steak carefully onto the plate. Spoon any remaining sauce and cheese from the dish over the top. Serve immediately while the cheese is still bubbly and the cauliflower is hot.