• Add 10 cups water and 2 tsp salt to a large pot (use same for 4 ppl). Cover and bring to a boil over high heat.
• Meanwhile, cut cauliflower into bite-sized pieces.
• Peel, then cut half the onion (whole onion for 4 ppl) into 1/4-inch pieces.

• Add cauliflower and 1 tbsp (2 tbsp) oil to an unlined baking sheet.
• Season with half the garlic salt and pepper, then toss to coat.
• Roast in the middle of the oven until golden-brown, 14-16 min.

• Meanwhile, add rigatoni to the boiling water.
• Cook uncovered, stirring occasionally, until tender, 10-12 min.
• Reserve 1/2 cup (1 cup) pasta water, then drain and return rigatoni to the same pot, off heat.

• Heat a large non-stick pan over medium heat.
• When hot, add 1 tbsp (2 tbsp) butter, then sausage and onions to the pan. Season with salt and pepper. Cook for 4-6 min, breaking up sausage and stirring often, until onions have softened and sausage is cooked through.** 
• Sprinkle flour and remaining garlic salt over sausage and onions.
• Cook, stirring often, until onions are coated, 1 min.
• Add cream and 1/2 cup (1 cup) milk, then bring to a boil.
• Once boiling, cook, stirring often, until sauce thickens, 1 min.
• Remove from heat, then add spinach. Stir until wilted, 1 min.

• Add cheese, sauce, half the reserved pasta water and cauliflower to the pot with rigatoni.
• Stir until cheese melts, 1 min. (TIP: For a lighter sauce consistency, add more reserved pasta water, 1-2 tbsp at a time.)
• Season with salt and pepper, to taste.

• Divide cheesy creamy cauliflower pasta between bowls.
• Sprinkle 1/4 tsp (1/2 tsp) chili flakes over top. (NOTE: Reference heat guide.)

If you've opted to add sausage, when the pan is hot, add 1 tbsp (2 tbsp) butter, then sausage and onions to the pan. Season with salt and pepper. Cook for 4-6 min, breaking up sausage and stirring often, until onions have softened and sausage is cooked through.** Follow the rest of the recipe as written.