Rinse the rice under cold water until the water runs clear. In a medium saucepan, combine rice, water or broth, and salt. Bring to a boil, then reduce heat to low, cover, and simmer for 18-20 minutes until rice is tender and liquid is absorbed.

While rice is cooking, pat the shrimp completely dry with paper towels. Season with salt and black pepper on both sides.

Heat olive oil and 2 tablespoons of butter in a large skillet over medium-high heat until the butter is melted and beginning to foam.

Add the shrimp in a single layer, working in batches if necessary to avoid overcrowding. Cook for 2-3 minutes without moving them, allowing them to develop a golden-brown crust.

Flip the shrimp and cook for another 2 minutes until they turn pink and opaque. Remove shrimp from the skillet and set aside on a plate.

Reduce heat to medium and add the remaining 2 tablespoons of butter to the same skillet. Once melted, add minced garlic and red pepper flakes if using. Cook for 30-60 seconds, stirring constantly, until fragrant but not browned.

Return the cooked shrimp to the skillet and toss to coat with the garlic butter. Add fresh lemon juice and half of the chopped parsley, stirring to combine.

Fluff the cooked rice with a fork and stir in butter and remaining parsley until well combined.

Serve the garlic butter shrimp immediately over the herb rice, drizzling any remaining sauce from the skillet over the top. Garnish with additional parsley and lemon wedges if desired.