In a large skillet, cook the ground beef and onions over medium heat until the meat is cooked and the onions are soft, about 10 mins. Drain off any excess fat. Season the meat with the grill seasoning. remove from the heat and sed aside.
In a 4-quart saucepan, melt the butter over medium heat. Whisk in the flour and cook for 1 minute, stirring constantly. Whisk in the milk and cook until the mixture begins to thicken. Add the cheddar and stir until melted.
Pour the cheese sauce onto the meat and stir to combine evenly. Transfer this mixture to a 3-quart baking dish. Top the meat mixture with the frozen fries. Bake for 40 to 45 minutes, until the fires are cooked and the mixture is bubbling.
For the Fry Sauce:
In a small bowl, mis together the ketchup, mayo and hot sauce to taste. Drizzle the sauce onto the cooked casserole and garnish with any optional toppings you desire. Serve hot, enjoy!
DIY Grill Seasoning: Combine 2 tbsp kosher salt, 2 tbsp black pepper, 2 tbsp garlic powder, 1 1/2 tsp onion powder, 1 1/2 tsp crushed red pepper and 1 tsp smoked paprika in a small bowl and whisk to combine. Store airtight at room temperature for up to 6 months!Recipe from The Cookies and Cups Cookbook by Shelly Jaronsky