In a large bowl, mix the minced beef, parsley and gluten free breadcrumbs together with the egg, garlic powder, salt, and pepper.
Once combined, roll the mixture into evenly sized meatballs. This amount of mixture should make approximately 10 - 12 small meatballs.
Heat a large non stick pan. Once hot, add the rapeseed oil and a tbsp of butter.
Once the butter has melted, add the meatballs and cook - turning regularly - until browned all over, and cooked through.
Using a slotted spoon, transfer the meatballs to a plate. Cover with tin foil and set aside while you make the sauce.
Reduce the heat to low. Add the butter. Once melted, add the gluten free flour. Cook the flour and butter together over a low heat for 3-4 minutes.
Increase the heat to medium-high and slowly add in the beef stock and double cream.
Once boiling, add the meatballs to the sauce. Then reduce the heat to a simmer and cook for 5-8 minutes until the sauce has reduced to a desirable consistency.
Serve with boiled rice or mashed potatoes.