Slow Cooker Low Carb Gluten Free Salisbury Steak

Ingredients

• 2 tsp olive oil
• 1 cup chopped onion
• 2 pounds grass fed ground beef
• 1/4 cup ground flaxseed
• 1 cup crushed pork rinds
• 1/2 tsp onion powder
• 1/2 tsp salt
• 1/4 tsp pepper
• 2 eggs
• 2 cups low sodium beef broth (divided)
• 8 ounces baby bella mushrooms
• 2 tbsp arrowroot powder
• 2 tbsp tomato paste
• 1 tbsp red wine vinegar
• 1 tsp Worcestershire sauce
• 1 tsp ground dried mustard
• 1 tsp garlic powder