Remove the leaves from your cauliflower. Trim the stem off but leave the core intact.
Slice your cauliflower into roughly 3/4" steaks. You will get a few good steaks from each head. Any loose florets that fall off keep we are using those too.
In a small bowl mix together olive oil, garlic powder, paprika, salt and pepper. Brush both sides of cauliflower (steaks and florets) with oil mixture.
Place cauliflower (stead and florets) onto a heated grill. Allow to cook until it begins to char (6 to 8 minutes) flip and cook on the other side for the same amount of time.
After flipping the cauliflower layer the shredded cheese on top of the cauliflower and allow to completely melt.
Remove from the grill and top with ranch, bacon and green onions.