Instructions

1. Soak anchovy in a small bowl of warm water for 30 minutes. Meanwhile, soak capers in another bowl of warm water for 10 minutes. Drain capers and repeat soaking process twice more. Drain, then filet, anchovy, discarding bones. Chop anchovy filets and peeled garlic together to make a fine paste and set aside. Drain capers, coarsely chop, and set aside.
2. Heat 2 tbsp. of the oil in a heavy medium skillet over medium heat. Add unpeeled garlic and cook, stirring occasionally, for 2-3 minutes. Add potatoes, season to taste with salt and peper, and cook until potatoes are lightly browned, about 5 minutes. Add half the rosemary and sage and cook until garlic and potatoes are tender, 2-3 minutes more.
3. Meanwhile, heat an enameled cast-iron casserole or othe rheavy pot with a tight-fitting lid over medium-high heat and add remaining oil. Season chicken with salt and pepper. Working in 2 batches, brown chicken all over, 4-6 minutes, transferring pieces to a dish as done. Add anchovy-garlic and capers to pot and cook, stirring with a wooden spoon, for 20-30 seconds. Add tomato paste and cook, stirring, for 30 second or so. Stir in wine and stock. Return chicken to pot, turning to coat, then add remaining rosemary and sage. Reduce heat to medium-low, cover pot, and simmer until chicken is cooked through, 20-25 minutes. Remove pot form heat, transfer chicken to a plate, and set aside.
4. Beat egg yolk and lemon juice together in a bowl. Ladle about 1⁄4 cup of the sauce from pot into egg mixture, stirring vigorously to prevent egg from curdling. Return chicken to pot, coating pieces with sauce. Serve chicken and sauce on a warm serving platter with potatoes, garlic, and herbs.