Preheat broiler. In a small bowl, mix together butter and cinnamon.
Spread one-quarter of cinnamon butter on each slice of bread. Top with 1 tsp (5 mL) brown sugar and one-quarter of pear slices arranged in single layer. Sprinkle remaining sugar on top of pears, dividing evenly.
Place bread on rimmed baking sheet. Broil until sugar melts and begins to caramelize, 1 to 2 min.