Gather all ingredients.
Whisk together stock, cream, flour, soy sauce, ½ teaspoon pepper, and ½ teaspoon rosemary in a large saucepan over low heat until smooth.
Cook, stirring occasionally, until thickened, about 10 minutes.
Stir in thawed meatballs, and continue cooking until meatballs are heated through, about 5 more minutes. An instant-read thermometer inserted into the center of the meatballs should read at least 160 degrees F (71 degrees C).
Taste and adjust seasonings before serving.
