1: Place the ground beef in a large bowl.
2: Add the salt, pepper, dry mustard, and cayenne, and mix well with a fork.
3: Add the ketchup, coconut aminos, apple cider vinegar, egg, and almond flour and gently mix until well combined.
4: Cover the bowl with plastic wrap and refrigerate for 2 hours or up to overnight.
5: Meanwhile, heat 2 tablespoons of clarified butter in a large nonstick sauté pan over medium heat.
6: Add the onions, mushrooms, and salt, stirring continuously until onions are transparent and mushrooms are brown (about 5-7 minutes).
7: Add the arrowroot, stirring to coat the mushrooms, followed by the ketchup and coconut aminos.
8: Add the chicken stock, increase heat to medium-high and bring to a low boil, then simmer until the sauce thickens (about 10 minutes).
9: Divide the meat mixture into four equal parts and form thick oval patties.
10: In a large sauté pan over medium heat, add the patties and cook until brown (about 2 minutes).
