Butter, white wine, capers, and fresh rosemary and sage make an unbelievable pan sauce for tender pork loin in this traditional Roman dish.
Pound pork slices to 3/8 inch thick, season with salt and pepper, and dredge in flour, shaking off excess. Transfer to a wire rack, and let stand 10 minutes.
Heat 1 tablespoon oil in a large saute pan over medium-high heat, and then add 1 tablespoon butter and melt, swirling to coat bottom of pan. Add 3 pork slices in a single layer and cook, flipping once, until both sides are golden brown and pork is cooked through, about 4 minutes total. Transfer to a serving platter and loosely cover with foil. Repeat.
Add capers and herbs and cook over medium-high heat, stirring, just until fragrant, less than 30 seconds. Add wine and cook until reduced by half. Stir in remaining tablespoon butter and pour sauce over pork. Add arugula to platter and drizzle with oil.