Rinse 1 lb chicken hearts under cold water. Trim any excess fat, connective tissue, and remove visible blood vessels. Pat hearts dry thoroughly with paper towels.

Make marinade

In a medium bowl combine 2 tbs olive oil, 2 tbs soy sauce, 1 tbs lemon juice, 2 cloves minced garlic, 1 tsp smoked paprika, 1 tsp ground black pepper, 0.5 tsp kosher salt and 1 tsp brown sugar. Whisk until sugar dissolves and mixture is uniform.

Marinate

Place trimmed, dried chicken hearts in the bowl with the marinade. Toss to coat all pieces. Cover and refrigerate for 30 minutes to 2 hours. If short on time, marinate for at least 15 minutes at room temperature.

Cook & Finish

Sear hearts

Heat a large skillet or cast-iron pan over medium-high heat until hot. Add 1 tbs butter and let it foam. Remove hearts from marinade, letting excess drip off, and add them in a single layer to the hot pan. Cook undisturbed 2–3 minutes to develop a brown crust, then stir or flip and cook another 2–3 minutes until evenly browned and just cooked through (internal temp about 165°F/74°C). Total cook time about 5–7 minutes depending on size.

Reduce marinade

While the hearts cook, pour the reserved marinade into a small saucepan and bring to a boil for at least 1–2 minutes to kill any raw juices, then simmer 1–2 minutes until slightly reduced. Alternatively, after removing hearts from the pan, deglaze the skillet with the marinade and simmer for 1–2 minutes to concentrate flavor.

Finish with aromatics

When hearts are nearly done, sprinkle 0.25 tsp red pepper flakes over them and add the reduced marinade or deglazing liquid back to the pan. Toss to coat and let the sauce cling to the hearts for 30 seconds. Remove from heat and stir in 2 tbs chopped parsley and any remaining 0.5 tbs butter to give a glossy finish.

Serve

Transfer hearts to a serving plate. Season to taste with extra salt or pepper if needed. Serve immediately with lemon wedges (4) alongside for squeezing over the hearts.