In a medium bowl, combine finely chopped parsley, cilantro, minced shallot, and garlic. Add dried oregano, red pepper flakes, red wine vinegar, fresh lemon juice, kosher salt, and black pepper. Mix until well blended, then whisk in 6 tablespoons of extra-virgin olive oil until the mixture is loose and glossy. Taste and adjust seasoning as needed.

Portion out one-third of the vibrant chimichurri sauce and set it aside in a small bowl for serving later.

Pat the large shrimp dry with a paper towel. Toss the shrimp in the remaining chimichurri until evenly coated. Allow them to marinate at room temperature for 10–15 minutes.

In a large skillet, heat 1 tablespoon of neutral oil over medium-high heat until the oil shimmers.

Carefully place marinated shrimp in a single layer in the hot skillet, sear for 1–2 minutes on each side until they are pink and opaque.

Once all the shrimp are cooked, remove the skillet from heat. Toss the shrimp with the reserved chimichurri sauce and serve immediately.