1. For the crêpe batter, whisk together the flours, sugar, and salt. In a separate bowl, whisk the coconut milk, eggs, and pandan extract with 1 cup of water. Add the dry ingredients to the wet, whisking until smooth, and adding more water if necessary to make a fairly thin batter. Cover and refrigerate for at least 30 minutes, or overnight.

2. While the batter is resting, make the sauce: In a medium saucepan over medium heat, whisk together the coconut milk, brown sugar, and vanilla bean. Bring to a simmer, stirring occasionally, until slightly thickened but still pourable, about 25 minutes. Keep warm over low heat while you make the crêpes, or reheat just before serving.

3. Heat an 8-inch nonstick skillet over medium-low heat until hot. Whisk the crêpe batter and add a little water to the batter if needed to make it pourable. Pour about 3 tablespoons batter into the pan and tilt to coat the bottom. Cook until the crêpe is just set and the edges are starting to curl, about 1 minute. Flip the crêpe with a spatula and cook until just cooked through, about 20 seconds more. Transfer the crêpe to a plate. Make crêpes with the remaining batter, stacking them on the plate as you go.

4. Just before serving, reheat the sauce. Thinly slice the bananas and add them to the sauce. Cook over medium heat for 2 to 3 minutes, to soften the bananas a little and warm them through.

5. To serve, place one crêpe on each serving plate. Spread a generous amount of the bananas and sauce over the lower half of each crêpe and fold over. Serve with a scoop of ice cream on the side.