Put the sugar and whole milk into a pot and cook until the sugar has just dissolved about 60 degrees Celsius, 140 degrees Fahrenheit.
Shift the cocoa powder into, a bowl, and whisk together with the rice flour.
When the sugar dissolved, add unsalted butter and semi-sweet chocolate and whisk to combine.Gradually Add the warm milk mixture to the dry ingredients. Add in Rum and egg yolk and the egg.Whisk well and let it sit while preparing the mold. Start preheating the oven to 200 degrees Celsius, 392 Fahrenheit.
Brush softened unsalted butter inside the mold.
Apply a generous amount of butter throughtly to release easily and maintain their shape.If you have oil spray, use it to make it even more easy releasing. Just before baking, stir the batter to make it even, then pass through a sieve and transfer to a jug for easy handling.Fill the mold just below the edge. Pop in the oven and immediately reduce the temperature to 190 degrees Celsius, 374 degrees Fahrenheit, and bake for 30 to 35 mins for the small cannele, 45 to 50 mind for the large cannule.If the The cake pop out from the mold while baking, take out and tap onto the counter to put them in place, otherwise the top is not browned. And, to make it even more delicious, dip in melted chocolate and cover the top.