1 (24-ounce) container prepared mashed potatoes, heated according to package directions
Garnish: fresh thyme
Instructions
In a 12-inch cast-iron skillet or braiser, melt butter with olive oil over medium-low heat.
Add onions and garlic; cook, stirring occasionally, until softened and lightly browned, about 25 minutes. Stir in flour; cook, stirring occasionally, for 5 minutes. Stir in broth, thyme, salt, and pepper; bring to a boil. Reduce heat; simmer until slightly thickened, about 10 minutes.
Preheat oven to broil.
Stir in meatballs; cover and cook for 5 minutes. Sprinkle cheese onto meatballs.
Broil 6 inches from heat until cheese is melted and lightly browned, 3 to 5 minutes. Serve with mashed potatoes. Garnish with thyme, if desired.
Recipe by Southern Cast Iron at https://southerncastiron.com/french-onion-meatballs/