Steam cauliflower florets in the microwave according to package directions.
Add the cauliflower to a food processor and process until smooth.
Transfer the mashed cauliflower to a mixing bowl and add the butter, salt, garlic powder, and sour cream. Mix until combined. Mix in half of the cheddar cheese.
Transfer mixture to a heatproof serving bowl and top with the remaining cheese. Heat in the microwave or oven just until cheese is melted. Top with bacon and chives.
