Steps

• Wash the mussels well under running water. Scrape them and remove the beard. Place them in a pan with a clove of garlic, a few parsley leaves, a piece of chili pepper, and the beer. Cover with the lid and let the shells open. As soon as they open, turn off the heat and remove them from the pan. Strain the liquid with a fine-mesh strainer, which will be used to moisten the bread crumbs. Open the mussels and keep the largest ones attached to the half shell. Chop the remaining ones that will go into the filling.

  

• Put the breadcrumbs in the mixer along with the washed and dried parsley. Pour the mixture into a bowl, adding a bit of the strained liquid. You can also replace it with milk or water, but in my opinion, if the mussels are well cleaned and their origin is known, the liquid obtained from their opening gives more flavor. Add two tablespoons of grated Parmesan cheese and the chopped mussels. Mix well to obtain a firm mixture like for meatballs. Do not add salt.

  

• Fill the half shells with the attached mollusk using this filling and press well. Arrange the mussels in a baking dish lined with parchment paper. Sprinkle with a tablespoon of Parmesan and one of Pecorino. Drizzle with a little oil and a few tablespoons of the remaining strained liquid. Bake in a hot oven at 428 degrees Fahrenheit and let gratinate for 20 minutes.