Aguachile

Fill a medium bowl with ice water. In a medium saucepan, add 6 cups water, 2 slices onion, the garlic clove, and 2 teaspoons salt. Bring to a boil.

Remove the saucepan from the heat and add the shrimp. Let stand until the shrimp are pink and just cooked through, about 1 to 2 minutes. Drain well, then immediately transfer the shrimp to the ice water to stop the cooking.

Drain again and pat dry. Slice each shrimp lengthwise along the back, cutting about halfway through so the shrimp opens slightly and lays flat.

In a molcajete or mortar and pestle, grind the serrano chile with 1 teaspoon salt and garlic powder until broken down. Add the cilantro and continue grinding until a rough paste forms, then stir in the lime juice. Taste and add additional salt as needed (I add another teaspoon for 2 teaspoons total).

Add the shrimp, remaining raw onion, and cucumber to the molcajete and toss to combine. If using a serving platter, arrange the shrimp and vegetables and drizzle with sauce.

Let stand 5 minutes to blend flavors, then serve with tortilla chips or saltine crackers and your favorite toppings.