Shrimp Vuelve a la Vida

Preparation

1. Step 1

   Cut 1 medium red onion in half through root end; set 1 half aside. Cut other half in half again (so you have 2 quarters). Coarsely chop 1 onion quarter and thinly slice the other quarter; set aside separately.

   Step 2

   Combine 2 smashed garlic cloves, 1 Tbsp. black peppercorns, and reserved red onion half in a large saucepan. Pour in 10 cups water and season generously with kosher salt (water should taste briny, like the ocean). Bring to a boil, then reduce heat and simmer 15 minutes.

   Step 3

   Return liquid to a boil. Add 1 lb. large shrimp, peeled, deveined, and cook until bright pink and cooked through, about 1½ minutes. Using a slotted spoon, immediately transfer shrimp to a large bowl of ice water and let cool 2 minutes; drain and pat dry. Slice shrimp in half lengthwise and transfer to a plate. Chill while you prepare the sauce.

   Step 4

   Pulse 1 plum tomato, coarsely chopped, ½ cup coarsely chopped cilantro stems, and reserved chopped red onion in a food processor or blender until mostly smooth. Transfer to a large bowl. Whisk in 1 cup fresh lime juice, 1 cup ketchup, 1 Tbsp. plus 2 tsp. distilled white vinegar, 1 Tbsp. plus 2 tsp. Tabasco, 1 Tbsp. Diamond Crystal or 1¾ tsp. Morton kosher salt, 1 Tbsp. Worcestershire sauce, 2 tsp. Aji-No-Moto umami seasoning (if using), 2 tsp. sugar, and 2 cups cold water until combined. Add shrimp; toss to coat.

   Step 5

   Divide shrimp and sauce among shallow bowls. Top with 1 large ripe avocado, thinly sliced, dividing evenly, and reserved sliced red onion. Scatter cilantro leaves with tender stems over. Serve with saltine crackers or corn tostadas and lime wedges alongside.