1. Make the lamb: Preheat the oven to 350°. Pat the lamb dry with paper towels and season with salt and pepper. Set aside at room temperature while you make the gremolata.

2. Place the hazelnuts on a rimmed sheet pan and toast in the oven until golden brown, 6 to 8 minutes. Transfer the hazelnuts to a plate to cool, then roughly chop. In a small bowl, mix the toasted hazelnuts with the parsley, lemon zest, garlic and ¼ teaspoon salt and set aside.

3. In a large grill pan or oven-safe skillet set over medium-high heat, heat the olive oil. Sear the lamb in the pan until golden brown on each side, about 5 minutes per side. Transfer the pan to the oven and cook until an instant-read thermometer reads 120° for medium-rare, 8 to 10 minutes longer. Remove from the oven, cover loosely with foil and let the lamb rest for 10 minutes.

4. Make the peas: Prepare an ice-water bath and set it on a work surface. In a medium saucepan of boiling, salted water, blanch the peas until they are just tender, 1 to 2 minutes. Strain the peas through a fine-mesh sieve and plunge them into the ice water to stop the cooking. Dry the peas on a kitchen towel and then transfer to a food processor. Add the olive oil, salt and pepper and purée until smooth.

5. Carve the lamb into individual chops and divide the pea purée and lamb chops among 4 plates. Top with the hazelnut gremolata and serve.