In a large lipped saute pan, warm pan over medium high heat for 3-4 minutes. When pan is hot but not smoking, add avocado oil and thinly-sliced steak in a single layer.
Leave undisturbed and season steak with half of the salt, granulated garlic and thyme leaves. After 2-3 minutes and steak releases, flip to the second side and brown another 1-2 minutes. Transfer steak to a medium bowl and set aside.
Return pan to medium-high heat and add peppers, onions, mushrooms, remaining salt and black pepper to the pan. Toss to coat in oil- add more oil if needed. Let saute for 5-7 minutes until vegetables are softened and lightly caramelized.
To the vegetables, add all pan sauce ingredients, scraping brown bits from the bottom of the pan. Let simmer for 5 minutes to reduce. In the final 2 minutes of cooking, return steak back to pan to warm through.
Garnish skillet with shaved pecorino and more picked thyme. Serve solo or with warm slider rolls on the side.