How to Make It
Heat 1 tablespoon butter in a large cast-iron skillet over medium-high. Sprinkle pork with 1/2 teaspoon salt and 1/2 teaspoon pepper. Add pork to pan; cook, turning to brown all sides, until a thermometer inserted in the center registers 145°F, about 15 minutes. Place pork on a cutting board; let stand 10 minutes. Cut into 12 slices.
Melt remaining 1 1/2 tablespoons butter in skillet over medium. Add onion, bell pepper, garlic, and thyme; sauté 3 minutes. Move onion mixture to one side of pan; add collard greens to other side of pan. Cook 2 minutes. Add black-eyed peas and vinegar to greens; cook 1 minute. Stir together onion mixture and collard mixture. Stir in remaining 1/4 teaspoon salt and remaining 1/4 teaspoon pepper. Serve with sliced pork.