Preheat your oven to 400 degrees F. Line a baking sheet with parchment paper and brush the paper with 1 tablespoon of oil or coat it with non-stick cooking spray. (Depending on the size of your cauliflower you might need two baking sheets to cook everything at the same time.)
Place a large skillet over medium heat and cook the bacon until crispy, around 5-7 minutes. Then transfer to a paper towel-lined plate to drain.
Remove the leaves and the lower part of the stem from the cauliflower head. Then cut the cauliflower into ¾-inch to 1-inch slices, yielding about 3 slices. Cut any remaining cauliflower into florets. Place the slices on the prepared baking sheet. (see note)
Mix 5 tablespoons of olive oil with paprika powder, garlic powder, salt, and pepper. Brush the mixture over the cauliflower steaks.
Bake for 25-30 minutes depending on how tender you like your cauliflower.
Carefully remove the baking sheet from the oven, sprinkle the cheese evenly over the cauliflower, and bake for another 5-10 minutes until the cheese has melted.
Remove from the oven and sprinkle with bacon and green onion. Serve warm with sour cream.
Notes
I love to use the rendered fat from the bacon to supplement the oil used. Just take as many tablespoons of bacon grease as you can get from the skillet and then add enough olive oil to equal 5 tablespoons.
In case you have a lot of small florets, just add them to a bowl, and sprinkle some paprika and garlic powder, salt, and pepper over it. Add some oil and toss. Place them in between the whole cauliflower slices.
Make this a vegetarian dish by omitting the bacon.