Steam or roast cauliflower until just tender. (Avoid overcooking!) Set aside on a towel to remove excess moisture.
In a saucepan, heat heavy cream over medium heat. Add cream cheese, garlic powder, mustard powder, salt, and pepper. Whisk until smooth.
Remove from heat and stir in 1 cup of cheddar cheese until melted and creamy.
Combine cauliflower with cheese sauce in a bowl and mix well.
Transfer mixture into baking dish. Top with remaining ½ cup of cheddar and optional crunchy topping.
Bake for 20–25 minutes, until bubbly and golden on top.
Let cool for 5 minutes before serving. Enjoy!