– 1 pound ground beef – ½ cup yellow onion finely chopped – 1/2 cup breadcrumbs * – 1 large egg beaten – 1 Tbsp ketchup – 2 teaspoon Dijon mustard – 1 tsp Worcestershire sauce – 1/2 teaspoon dried oregano – 1/2 teaspoon sea salt to taste – ¼ tsp black pepper to taste – 1 Tbsp avocado oil for cooking
– 1 Tbsp avocado oil – 2 tablespoons unsalted butter or more avocado oil – 1 cup yellow onion finely chopped – 2 cloves garlic minced – 8 ounces cremini mushrooms sliced – 2 Tbsp gluten-free all-purpose flour or regular all-purpose flour flour** – 1 1/2 cups beef stock – 2 tsp dijon mustard – 1 tsp Worcestershire sauce – Salt and black pepper to taste