Preheat oven to 200 degrees C or 400 F.
Wash and cut cauliflower into florets and place into a large bowl.
Toss cauliflower with olive oil, ½ of the lemon (squeezed for juice), paprika, cayenne and salt, and pepper. (As you can see from the pictures above, I used slightly more paprika and cayenne because I love bold flavors. Season to your preference!)
Place on a baking tray with parchment paper or aluminum foil.
Roast on the middle rack for 15 minutes.
Remove from oven and flip the cauliflower.
Then place back into the oven, but now on the top rack for the remaining 10-15 minutes. (This will give the tops and edges some browning and caramelization)
When finished, squeeze the remaining ½ of the lemon juice over top of the cauliflower. Serve!