"What's more important to me than letting meat come to room temperature?" Rachael asks. "Making sure the meat is dry before it hits the skillet. I unwrap the meat, pat it dry, and leave it uncovered in the fridge for up to a day."
Preheat the broiler to high or turn a stovetop gas burner to high. Char the peppers, turning occasionally, until blackened all over, 10 to 12 minutes. Place in a bowl and cover with plastic wrap. Let rest until cool enough to handle, about 10 minutes. Using a paper towel, rub the skins off the peppers. Seed and coarsely chop the peppers.
Meanwhile, pat the steaks dry and season with kosher salt and pepper. Heat a large cast-iron skillet over medium-high.
In a food processor, pulse the chopped roasted peppers, bread, almonds, parsley, shallot, vinegar, crushed garlic, paprika, crushed red pepper, and half the lemon juice until finely chopped. With the machine running, gradually add the EVOO and pulse until a thick and slightly coarse sauce forms. Season the romesco sauce.
In another skillet, heat 2 tablespoons olive oil, two turns of the pan, over medium. Add the chopped garlic. Cook, stirring often, until aromatic, about 1 minute. Add the greens; season with salt, pepper, and nutmeg. Cook, tossing often, until the greens are just wilted, about 2 minutes. Mix in the remaining lemon juice. Remove from heat.
Add the remaining 1 tablespoon olive oil, one turn of the pan, to the hot cast-iron skillet. Add the steaks. Cook, undisturbed, until the steaks develop a crust, about 3 minutes. Turn the steaks and cook for 2 minutes more. Continue cooking, turning occasionally, for about 2 minutes more for medium-rare or 4 minutes more for medium. Transfer the steaks to a cutting board. Let rest for 5 minutes.
Add the two lemon halves, cut-side down, to the skillet. Cook until browned, about 2 minutes. Slice the steaks against the grain. Squeeze the charred lemon halves on top.
Divide the steaks among plates. Top with the romesco sauce. Serve the wilted greens and crusty bread on the side.