2. Drain the raisins, reserving the liquid. Discard the vanilla bean. Put the liquid back in the saucepan and bring to a boil. Reduce to about 1/3 cup, or until the syrup turns a deep golden color, 10 to 15 minutes. Watch carefully so the syrup doesn't burn. If it starts to foam, remove from heat immediately. The syrup will continue to thicken as it cools, and have a texture similar to light maple syrup. Cool completely.
3. Preheat the oven to 400 F.
4. Brush butter onto both sides of the bread slices. Bake for 8 to 10 minutes or until golden brown. Let cool completely.
5. To assemble: Put a slice of cheese on each toast. Sprinkle with a few raisins and drizzle syrup over the top.
Note: If you have any raisins and syrup left over, combine them and refrigerate in an airtight container. They will keep for 2 weeks.
Simple table salt can be transformative on food -- imagine unsalted potato chips or french fries. Paul Breslin, a professor who researches taste perception, explains how salt affects the taste of food.