12–16 Jimmy Nardello peppers, 8 Cubanelle peppers, or 8 oz. shishito peppers
Red wine vinegar (for serving)
Pound garlic, rosemary, and 2 Tbsp. oil with a mortar and pestle until pulverized. (Alternatively, finely grate garlic and finely chop rosemary. Combine in a small bowl and mix in the oil.) Season lamb chops on both sides with salt and black pepper. Coat all over with garlic paste and let sit at room temperature 30 minutes or cover and chill up to 12 hours.
Just before you are ready to grill the chops, make the herb salsa. Pound parsley and dill with mortar and pestle with a big pinch of salt until coarsely crushed. (Alternatively, finely chop the herbs and combine in a medium bowl.)
Finely grate zest from lemon into herbs, then slice lemon in half and squeeze in its juice. Stir in ½ cup oil; taste and season herb salsa with more salt if needed.
Prepare a grill for medium-high heat. Grill lamb chops, turning often to encourage fat to render and moving to a new spot on the grill whenever there’s a flare-up, until nicely charred on the outside but still pink in the center, 6–8 minutes. Transfer to a platter and let rest 5–10 minutes.
While the chops are resting, toss peppers in a medium bowl with enough oil to coat; season with salt.
Grill peppers, turning often, until skins are blistered and charred in spots and flesh is tender, about 3 minutes. Return to bowl, add a few dashes of vinegar, and toss to coat.
Serve lamb and peppers with herb salsa for spooning over.