Bring steaks to room temperature and season liberally with salt and pepper. Combine the paprika, cumin and coriander in a small bowl and rub into steaks. Prep your peppers, celery and onion while the steaks hang out.
Heat a cast-iron skillet over medium-high heat with oil 2 turns of the pan. Add steaks and brown, 8-10 minutes, turning occasionally; remove and let rest.
To the pan drippings, add another turn or two of oil then the peppers. Cook until brown, about 5 minutes, then add celery, onions and half of the garlic. Season with salt and pepper, toss 2-3 minutes more then deglaze pan with vinegar. Add honey, toss and remove pan from heat.
In another skillet, heat 2 tablespoons oil over medium-high heat. Add remaining garlic, swirl and wilt in spinach. Season with nutmeg, salt and pepper, and remove from heat.
Slice meat against the grain into 1/2-inch thick slices.
To serve, arrange 1/4 of the pepperonata on each dinner plate in an even layer. Top with 1/4 of the spinach leaving a rim of peppers around the edge then top spinach with sliced steak.