Combine 4 tablespoons butter, 4 minced garlic cloves, 2.5 tablespoons fresh parsley, 1/8 teaspoon red pepper flakes, and 1/2 teaspoon lemon juice in a small bowl, stirring until well mixed. Set aside at room temperature. Pat the ribeye completely dry with paper towels and season generously on both sides with 1 teaspoon flaky sea salt and 1/2 teaspoon freshly cracked black pepper. Peel and devein the 16 large shrimp if not already done, keeping tails on, then season lightly with 1/2 teaspoon salt. Trim the asparagus spears.
Heat 1/2 tablespoon olive oil in a large skillet over high heat until it just begins to smoke. Place the seasoned ribeye in the pan and sear for 3-5 minutes on the first side without moving it—this creates a golden crust. Flip and cook for 3-5 minutes on the second side until the internal temperature reaches medium-rare (about 130-135°F). Transfer to a plate and top with 1.5 tablespoons unsalted butter, allowing it to melt over the steak as it rests for 5 minutes. This resting period allows the juices to redistribute throughout the meat, keeping it tender and juicy.
While the steak rests, melt 2 tablespoons butter with 1 tablespoon extra virgin olive oil in a separate large skillet over medium heat. Add the trimmed asparagus spears, stirring to coat evenly. Add 4 tablespoons water and 1/2 teaspoon salt, then cover and cook for about 5 minutes until the asparagus is tender-crisp and the water has mostly evaporated. Season with 1/4 teaspoon black pepper and transfer to a serving plate.
In another large skillet, melt 2 tablespoons butter with 1 tablespoon olive oil over medium heat. Once foaming, add the seasoned shrimp from Step 1 in a single layer and cook for 2-3 minutes until they turn pink and begin to curl. Flip and cook the other side for another 2-3 minutes until cooked through. I like to avoid overcrowding the pan here—if your skillet is small, cook the shrimp in two batches so they sear properly rather than steam. Transfer the cooked shrimp to a clean plate.
Slice the rested ribeye against the grain into your desired thickness. Arrange the sliced steak, cooked shrimp from Step 4, and asparagus from Step 3 on serving plates. Spoon or dollop the garlic butter mixture from Step 1 generously over the shrimp and steak, allowing it to melt slightly from the residual heat. Serve immediately while everything is warm and the butter is still glossy.