Step 1: In a large pot, bring 8 cups of water to a rolling boil over high heat.
Step 2: Add the chopped cauliflower florets and elbow macaroni. Cook for about 8-10 minutes, until al dente.
Step 3: Drain the pasta and cauliflower in a colander and set them aside.
Step 4: In the same pot, reduce heat to medium, add milk and whisk in flour until slightly thickened, about 3-5 minutes.
Step 5: Stir in Cheddar shreds until melted and creamy. Add buttery spread, salt, and optional ingredients.
Step 6: Fold in the cooked cauliflower and macaroni until well coated.
Step 7: Preheat oven to 350°F (175°C). Grease a baking dish and pour in the mixture. Sprinkle with breadcrumbs.
Step 8: Bake for 20-25 minutes until golden and bubbly. Let cool slightly before serving.