Dust snails in flour. In a medium saute pan with olive oil over medium heat, add onions and garlic and saute until translucent, approximately 4 to 5 minutes. Add snails and rosemary and continue to saute for 2 minutes. Add vinegar. Saute for an additional 2 minutes. Season with salt and black pepper. Serve immediately with crusty bread.
Recipe courtesy of Dimitris Skarmoutsos of Nykterida in Hania, Crete