Start by preparing your vanilla layer. In a large mixing bowl, combine the rice flour, glutinous rice flour, and white sugar using a whisk until evenly distributed. Create a well in the center and pour in the evaporated milk, coconut milk, and vanilla extract. Stir everything together until you have a smooth, lump-free mixture.

Transfer this vanilla mixture to a heavy-bottomed saucepan and place over low heat. Stir constantly for 10-15 minutes until the mixture transforms into a thick, paste-like consistency that pulls away from the sides of the pan. Remove from heat and set aside to cool completely.

For the chocolate layer, whisk together rice flour, glutinous rice flour, cocoa powder, and brown sugar in your second mixing bowl until well combined. Add the coconut milk and vanilla extract, stirring until you achieve a smooth mixture without any cocoa lumps.

Cook the chocolate mixture in your second saucepan over low heat, stirring continuously for 10-15 minutes until it reaches the same thick paste consistency as the vanilla layer. Fold in the crushed peanuts during the last minute of cooking. Remove from heat and let cool completely.

While your mixtures cool, prepare the banana leaves by briefly heating them over an open flame or in a dry pan until they become pliable and bright green. Cut into rectangles approximately 8x6 inches. Lightly brush each piece with cooking oil to prevent sticking.

Take 2 tablespoons of cooled vanilla mixture and roll it between your palms or on a clean surface to form a rope about 4 inches long. Repeat with 2 tablespoons of chocolate mixture to create a second rope of similar length.

Place both ropes side by side and gently twist them together to create a spiral pattern, being careful not to blend the colors completely. You want distinct spiral stripes throughout.

Place the twisted suman on an oiled banana leaf rectangle. Roll the leaf around the suman, tucking in the sides as you go to create a neat package. Tie securely with kitchen string or strips of banana leaf.

Repeat this process until all your mixture is used up, creating individual wrapped portions. Arrange the wrapped suman in your steamer basket, making sure they don't overlap too much.

Steam the wrapped suman for 30 minutes over rapidly boiling water. The banana leaves will darken and the suman will feel firm when properly cooked.

Remove from steamer and let cool for 5 minutes before serving. Serve warm for the best texture and flavor experience.