Combine black sugar, granulated sugar, and water in a small saucepot. Bring to a boil over medium heat. Reduce heat to low and simmer for 5 minutes or until sauce is thick enough to coat the back of a spoon. Do not disturb mixture while simmering. Remove from heat and let cool. Mix with pancake syrup and set aside.
Combine dry ingredients in medium bowl (flour, sweet rice flour, baking soda, baking powder, and sugar). In a separate bowl, whisk together eggs, honey, and milk. Stir dry ingredients into wet, mixing until just incorporated.
Heat non-stick griddle over medium-low heat. Spray cooking spray, wiping away excess. Pour ¼ cup batter onto the pan to form one pancake. When bubbles arise, and pop, flip the pancake. Cook until golden brown on both sides. Remove and repeat with remaining batter.
Let pancakes cool slightly. Spread margarine on one side of each pancake. Drizzle syrup in the center of the pancake and top with other half. Serve at room temperature.
Notes
The syrup can be prepared up to 3 days in advance.