If the walnuts are not roasted, place them on a baking sheet and roast them in the oven at 350 F (180 C) in a conventional oven, or 320 F (160 C) in a convection oven, for 10 minutes. You can also toast them on a dry pan for 10 minutes over medium heat until fragrant and nutty.

Set aside to cool down

Place the walnuts, sesame seeds (if using) and 700ml water in a blender and blend until really smooth. Pour this into a large pot.

Add the sugar and cook over medium heat until the sugar has melted.

Stir in evaporated milk and salt and cook over medium-low heat for about 2 minutes

Combine rice flour with 70 ml of water and mix well to make a slurry. While one hand is stirring the walnut mixture, gradually pour in the rice flour slurry. The slurry will thicken the soup slightly. If you like it thicker, you can make a bit more of the rice flour mixture.

Serve the walnut dessert soup warm or at room temperature. It is delicious served with some ice as well on a hot summer day