Rinse peppers under cold water and pat dry. Slice off tops and bottoms, stand upright, and cut down along the inside to remove seeds and white ribs. Slice lengthwise into ½-inch strips; halve crosswise for shorter pieces. Keep sizes uniform so everything cooks evenly. If adding onion, slice it now. Measure out olive oil, salt, and pepper. Have everything ready before the pan goes on — sautéing moves fast.

Heat a large Skillet over medium heat. Add 1 tbsp olive oil per 2 peppers; warm 30–60 seconds until shimmering. Add pepper strips in a single layer — work in batches if crowded. Season with salt and pepper, stir to coat. Cook over medium heat, stirring every 2–3 minutes, for 6–10 minutes. At 6 minutes: slightly softened with snap. At 10 minutes: tender throughout with light color. For very soft peppers, cook 30–40 minutes over medium-low, stirring occasionally. Add garlic halfway through cooking. If browning too fast, add a splash of white wine or water and briefly cover to steam.

Pour the ½ cup extra-virgin olive oil into a large Cast Iron Skillet or heavy-bottomed Pot and set over medium-low heat. Add the sliced 8 cloves garlic thinly sliced and crumbled dried arbol chili peppers. Cook gently, stirring occasionally, until the 8 cloves garlic thinly sliced turns pale golden and fragrant, about 3–4 minutes. Do not let the 8 cloves garlic thinly sliced brown or it will turn bitter.

Increase the heat to medium-high. Add the 1 ½ lb large shrimp peeled and deveined, tails on in a single layer and cook for 1 minute without moving them. Flip each 1 ½ lb large shrimp peeled and deveined, tails on, sprinkle in the 1 tsp smoked paprika, and pour in the ¼ cup dry sherry such as Fino or Manzanilla. Cook for another 1–2 minutes, until the 1 ½ lb large shrimp peeled and deveined, tails on are just pink and curled and the ¼ cup dry sherry such as Fino or Manzanilla has reduced slightly. Remove from heat immediately — overcooked 1 ½ lb large shrimp peeled and deveined, tails on turn rubbery.