Heat olive oil in cast iron pan until oil is hot. If you do not wait until oil is hot enough its fine but it will take longer for the scallops to get that golden layer
Place scallops in cast iron side by side, not on top of each other. If you need to, pan sear them in batches. Cook the scallops for about 2-3 minutes on each side or until the scallops have developed a golden layer to your preference. Season with salt, pepper and red pepper flakes.
Transfer scallops to a plate. Turn head down to medium low. Add butter and garlic to the pan, cook until fragrant 1-2 minutes. Add cream and juice from one lemon and stir scraping the bottom of the pan.
Add scallops back to the pan, quartered lemons and top with fresh cilantro.
Remove from heat and serve