.  In a small bowl, whisk together the cornstarch and water to make a slurry. Turn heat to medium-high and stir sauce until it thickens enough to coat the back of a spoon, 60 to 90 seconds.
. Reduce heat to a simmer, and stir in ½ teaspoon salt, ½ cup heavy cream, and lemon juice. Taste and adjust salt and pepper as desired.
Slow Cooker Instructions:
. Follow instructions 1 to 7. Heat a large saute pan over medium-high heat, add oil, and brown meatballs on one side for 4 minutes, flip, and brown another 2 minutes. Transfer meatballs to a plate.
. Add 1 cup of unsalted beef broth, using a whisk to deglaze, and scrape any of the browned bits on the bottom of the pan into the liquid.
. In a small bowl, whisk together the cornstarch and water to make a slurry. Turn heat to medium-high and stir sauce until it thickens enough to coat the back of a spoon, 60 to 90 seconds. Transfer the sauce and browned meatballs to the slow cooker.
. Cover and cook meatballs 2 hours on “High”, or “Low” for 4 to 5 hours.
. Stir in ½ teaspoon salt, ½ cup heavy cream, and lemon juice. Taste and adjust salt and pepper as desired