Swedish Meatballs (Keto, Grain-free!)

Ingredients for Meatballs:

• 1-pound ground beef
• 1 tablespoon dried parsley
• ¼ teaspoon allspice
• ¼ teaspoon nutmeg
• ½ teaspoon garlic powder
• Salt and pepper, to taste
• ¼ onion, diced
• 2 tablespoons butter

Ingredients for Sauce:

• 4 tablespoons butter
• 1½ cups beef stock
• ½ cup heavy whipping cream
• ½ cup sour cream
• 2 tablespoons Worcestershire sauce
• ½ tablespoon Dijon mustard
• Salt and pepper, to taste
• 1 teaspoon xanthan gum