Pat the beef sirloin dry with a paper towel and season both sides evenly with the sea salt and black pepper.
Heat the extra virgin olive oil in a large stainless steel or cast iron skillet over medium-high heat until it begins to shimmer.
Place the beef in the hot skillet and sear for 3-4 minutes per side until a deep golden-brown crust forms, then remove from the pan and let rest on a cutting board.
While the beef rests, steam the green beans in a small pot with two tablespoons of water for 4 minutes until they are vibrant green and snappy.
In the same skillet used for the beef, add the sliced cremini mushrooms and sauté for 5 minutes until they release their moisture and turn golden.
Add the minced garlic and fresh thyme to the mushrooms, cooking for 1 minute until the aromatics are fragrant.
Pour in the beef bone broth and coconut aminos, using a wooden spoon to scrape the bottom of the pan to incorporate the flavorful browned bits.
Simmer the sauce for 3 minutes until slightly reduced, then slice the beef into strips, toss them back into the sauce to coat, and serve immediately over the cooked quinoa with the green beans.