In a large skillet, heat 1 tablespoon of avocado oil over medium heat.
Add the diced yellow onion to the skillet and sauté for about 3-4 minutes, or until the onion becomes translucent and fragrant.
Stir in the chopped baby bella mushrooms and minced garlic. Cook for an additional 3-5 minutes, allowing the mushrooms to soften and the garlic to become aromatic.
Add the ground beef to the skillet. Break it up with your spatula, cooking until browned and fully cooked through, about 5-7 minutes. Drain excess grease if necessary.
Sprinkle the dried oregano and sea salt over the beef mixture. If you're using coconut aminos or soy sauce, add that now. Stir well to combine all the flavors.
Gently fold in the baby spinach, stirring until it wilts and integrates into the mixture. This should take about 2 minutes.
Remove the skillet from heat and serve your 30-Minute Ground Beef and Mushroom Skillet hot.
