Step 1: Season the steaks generously with salt and black pepper on both sides. Allow them to sit at room temperature for 15-20 minutes while you prepare other ingredients.
Step 2: Heat 1 tablespoon of olive oil and 1 tablespoon of butter in a large, heavy-bottomed skillet or cast iron pan over medium-high heat until shimmering and hot.
Step 3: Carefully place the seasoned steaks into the hot skillet. Sear for 3-5 minutes per side for medium-rare, or adjust cooking time to your desired doneness. For medium-rare (130-135°F internal temperature), flip once and cook until a nice crust forms. Remove steaks from the pan and let them rest on a cutting board, covered loosely with foil.
Step 4: In the same skillet, reduce heat to medium. Add the remaining 1 tablespoon of butter. Add minced garlic and red pepper flakes (if using) and sauté for 1 minute until fragrant, being careful not to burn the garlic.
Step 5: Add the shrimp to the skillet and cook for 2-3 minutes, stirring occasionally, until the shrimp turn pink and opaque. Do not overcook.
Step 6: Pour in the chicken or vegetable broth and bring to a gentle simmer, scraping up any browned bits from the bottom of the pan. Let it simmer for 1-2 minutes.
Step 7: Stir in the heavy cream and bring the sauce back to a gentle simmer. Cook for 3-5 minutes, stirring occasionally, until the sauce slightly thickens. Season the sauce with salt and pepper to taste.
Step 8: Return the cooked shrimp to the sauce. Slice the rested steaks against the grain into desired thickness. Serve the sliced steak immediately with the creamy garlic shrimp and sauce spooned generously over top. Garnish with fresh chopped parsley.