Preheat your griddle to medium-high heat. I am using the Cuisinart 360 XL griddle for this cook.
Add some butter, then the ground beef, and chop the meat. Add salt & pepper to taste.
Place a cast iron skillet or any oven-safe pans on the other side of your griddle.
Add some butter with a drizzle of olive oil.
Add the chopped garlic, parsley and stir so the garlic doesn't burn.
Add the cooked ground beef and the marinara sauce and mix everything together. Let's cook for about 5 minutes, so the sauce starts to bubble.
Add the mussels into the sauce and give a good mix. Cover and let cook for about 5 minutes.
Garnish with fresh chopped parsley and serve with sliced toasted bread on some spaghetti noodles.