Finely chop the parsley. Peel the garlic cloves and press them.

Finely chop the rosemary. In a small food processor, combine the parsley, rosemary, garlic, and half the butter. Blend until it forms a paste. Add the olive oil and blend again.

Peel and thinly slice the shallots. Add them to the herb butter mixture and blend again. Add the remaining butter and blend until you have a smooth, firm paste. Refrigerate for 15 minutes. Drain the snails.

Sauté the snails over high heat for 5 minutes, then let them cool. Place one snail in each shell and fill with the shallot and herb mixture, pressing it in and smoothing the top.

Fill all the shells, then refrigerate for 1 hour. Arrange the snails on individual baking dishes (I serve 12 snails per person). Preheat the oven to 230°F (110°C).

Bake for about 20 minutes, watching carefully. As soon as the filling starts to bubble, they're done. Place the baking dishes on plates—ready to serve!

Serve immediately. Enjoy!