Cover bananas; let stand in a cool place for 36 hours. Strain through cheesecloth. Combine banana juice and Plain Syrup in a saucepan; bring to a boil. Reduce heat, and simmer 5 minutes. Remove from heat, and stir in banana extract and lemon juice. Store in an airtight glass container.
For each serving, place about 1 cup Banana Syrup in a glass. Add enough finely crushed ice to fill glass; stir gently.