Place frozen cauliflower in a microwave safe dish, cover with plastic wrap.

Microwave on high for 12-15 minutes. It should be VERY soft and easy to mash.

As the cauliflower is cooking, Cook bacon and onions together in a large frying pan over medium heat.

When bacon is fully cooked and onions are translucent, remove from heat, drain off the fat, set aside.

Once cauliflower is soft and mashable, drain well and add to a food processor, along the shredded cheese.

Blitz until very smooth. Add sour cream and mayonnaise, blitz once again until smooth and well combined.

Transfer cheesy cauliflower mixture to a large bowl.

Add drained bacon and onion mixture, stir well to combine. Stir in the green onions, then season with salt and pepper, to taste.

Transfer to an airtight container, chill in the fridge for at least 2 hours.

To serve, transfer to a serving bowl and garnish with sour cream, additional bacon, sliced green onions, and/or cheddar cheese, as desired.