Preheat the oven to 425F.
Scatter your hamburger patties, sliced onion, garlic, sliced mushrooms and thyme on a baking sheet and drizzle with avocado oil and season with salt and pepper all over.
Bake for 20 minutes at 425F then turn the oven to broil and cook for 2 more minutes to get a little extra browning on top of the meat and veggies.
Move the meat and half of the onions and mushrooms to a serving platter, then add the remaining garlic, onions, mushrooms and accumulated juices to a blender. Add 1 cup of beef bone broth and 1 Tbs liquid aminos to the blender, too, and blend for a full minute until you get a silky smooth gravy. If you used leaner meat, you might have less juices accumulated in the pan. In which case, add ¼ cup more broth to get a pourable gravy consistency.
Spoon some of the gravy over the top of your steaks on the platter and serve with the remaining gravy on the side.
