Steam cauliflower until cooked and tender, then place saucepan with cauliflower, lid off, aside to let the cauliflower dry out, drain and cool slightly. Use a tea towel or strainer to squeeze excess water out of the cauliflower. Set aside.
Chop bacon into small pieces and fry in a pan with the olive oil until brown and crispy. Set aside.
Place cauliflower in food processor and process until smooth and fluffy. Add butter, sour cream and garlic powder and process until the texture resembles that of mashed potatoes.
Transfer cauliflower mash into a bowl, add 3/4 of the cheese, chives and bacon, pepper and salt to taste and stir through until well combined.
Sprinkle leftover cheese, bacon and chives over the top. Serve immediately.