Drain frozen scallops thoroughly and lay out on paper towells to dry further
Place frozen spinach in a bowl and microwave until slightly cooked and thoroughly thawed
Heat 2 Tbsp oil in a skillet and saute chopped onion until golden and caramelized (about 5 min).
Add garlic and saute for 30 seconds to 1 minute. Add paprika, zest, salt, and nutmeg and stir together. Add heavy cream to skillet and cook over medium heat until reduced by half and fairly thick.
Lower heat and add spinach and heat through (about 3-5 minutes). Set aside
In another skillet, heat 2 Tbsp oil until smoking (very hot). Make sure scallops are as dry as possible and season with salt, pepper and ground fennel
Place scallops in skillet in a circular pattern starting at bottom of skillet (so you know where you started). Sear for a couple of minute (peak at one of them to make sure the bottom side is brown and seared). With tongs, turn them over in the same pattern as you laid them down.
Cook for only a minute on the flip side and remove to a platter. Serve with still-warm creamed spinach.