Step 1

Melt 1 stick cut-up unsalted butter in a large stainless steel skillet over medium heat. Add 1/2 thinly sliced medium yellow onion and 1 thinly sliced medium serrano pepper. Cook, stirring occasionally, until starting to soften, 4 to 6 minutes.

Step 2

Reduce the heat to medium-low. Stir in 3 minced garlic cloves and cook until fragrant, about 1 minute. Stir in 1/2 cup Salsa Huichol, 1/2 cup ketchup, 1/2 teaspoon kosher salt, and 1/4 teaspoon black pepper. Return the heat to medium and bring to a simmer. Simmer until slightly thickened, 2 to 3 minutes.

Step 3

Stir in 2 pounds raw peeled and deveined large shrimp and cook, stirring occasionally, until the shrimp are just cooked through, 6 to 8 minutes.

Step 4

Remove the skillet from the heat. Taste and season with more kosher salt and black pepper as needed. Stir in 2 tablespoons lime juice. Serve with thinly sliced cucumber rounds, thinly sliced red onion, and tostadas if desired.