Combine parsley, oregano, minced garlic, red pepper flakes, olive oil, and red wine vinegar in a food processor or blender. Blend until the mixture is smooth and slightly chunky, then transfer to a bowl to form your chimichurri sauce.
Pat the shrimp dry with paper towels to remove excess moisture, which helps them get a nice sear.
Add the shrimp to the bowl with half of the chimichurri, tossing gently to coat each piece evenly. Let them marinate for 5 minutes to absorb the herbaceous flavors.
Heat a skillet or grill pan over medium-high heat until hot, and add a little oil to prevent sticking.
Add the marinated shrimp to the hot pan in a single layer, hearing a satisfying sizzle as they hit the surface.
Cook for 2-3 minutes per side, flipping once, until the shrimp are pink, opaque, and slightly charred at the edges.
Remove the shrimp from the heat and transfer to a serving plate, letting them rest briefly as the flavors meld.
Drizzle the remaining chimichurri over the cooked shrimp to add fresh, herby brightness and a slight oily gloss.
Garnish with extra herbs if desired, and serve immediately for the best flavor and texture.
