Place the periwinkles (or thawed snails) in a medium bowl, uncovered, and let them sit in the refrigerator until ready to use.

Rinse them under cold running water for 30 minutes.

Drain well.

In a shallow earthenware casserole dish or Dutch oven, heat the olive oil over medium heat.

Add the finely chopped onion and cook, stirring, until wilted and transparent, about 5 minutes.

Add the seeded and chopped dried red chili peppers, finely chopped garlic, thinly sliced chorizo, and cubed Serrano ham or prosciutto.

Cook, stirring, for about 5 minutes more.

Sprinkle the mixture with all-purpose flour and ground paprika, then stir to coat everything evenly.

Stir in the tomato sauce, dry white wine, periwinkles (or snails), salt to taste, and 2 tablespoons of the chopped parsley.

Bring the mixture to a boil over medium-high heat, then reduce the heat to low and simmer, stirring occasionally, for about 30 minutes more.

Sprinkle the dish with the remaining 2 tablespoons of chopped parsley before serving.

If using an earthenware dish, serve hot directly from the dish.

Alternatively, transfer to a serving platter.

If you prefer, you can cool the dish, cover it, and refrigerate it overnight.

Reheat over medium heat before serving.