Preheat the oven to 350˚F.
Melt 1 tablespoon butter in a pan, add the flour and cook, stirring constantly for 2 minutes. Gradually stir in the beef stock and cook, stirring constantly for 5 minutes more. Add the tomatoes, tomato paste, sugar, tarragon and oregano. Season well and simmer for 30 minutes.
Mix the ground beef or turkey, onion, garlic and paprika with the toasted oats, and season to taste. Shape the mixture into 12 meatballs.
Heat the oil and the remaining butter in a skillet and fry the meatballs, turning them until brown all over. Place in a deep casserole dish and pour the tomato sauce over them, cover and bake for 15 minutes.