Preheat Blackstone to medium high heat. Add sausage to cook completely. Use you Blackstone scraper or spatula to chop meat as you would taco meat.
Place tin tray directly on clean side of the Blackstone, add a drizzle of extra virgin olive oil. About 2 tablespoons.
Add garlic, crushed red pepper and a few whole pieces of parsley roughly chopped to the oil, including the stems. Shake tin or stir around to cook garlic 1-2 minutes or just until fragrant. Be sure not to burn garlic.
Add the cooked sausage and marinara sauce to the tin and mix everything together. Let cook a few minutes or just until the sauce starts to bubble.
Add the mussels into the sauce and mix well, spreading the mussels out evenly. Cover with foil and let cook 3-4 minutes gently shaking pan a couple times during to help make room for mussels to open.
Remove foil, mix mussels and allow them to cook 30 more seconds. This will help any mussels that need more room to open. Remove tin tray, garnish with fresh chopped parsley and enjoy!