【清热解暑】紫薯绿豆汤 Green Bean Soup with Purple Sweet Potato

被染成一片紫的糖水，煞是好看。

紫色给我浪漫，柔和的感觉，所以当初有了自己的房子我就认定主人房的墙一一定要漆上紫色。

我家的绿豆汤从来就只有两种吃法，单单只有绿豆，不然就是加入椰浆/椰糖，加入番薯的吃法是效仿舅母煮的。

加入了番薯后的绿豆汤绿豆的味道被分散不少，却添加了番薯的香味，却也不失为另一道简单美味的甜品。

紫薯绿豆汤（闷烧锅）

材料：
绿豆 150克
清水 2公升
紫薯 （中）一个，切块（用其他番薯也行）
班兰叶1把，打结
冰糖 适量

做法：
1）绿豆用清水洗几遍，挑去坏豆，倒入闷烧锅内锅加入清水大火煮滚。加入番薯，继续煮约10分钟。
2）把内锅移入外锅内。绿豆煮软到个人喜欢的程度后（大约20-30分钟，视个人喜好和个别闷烧锅而定），移到煤气炉，加入适量冰糖煮至糖溶化，把班兰叶取出即可享用。

注：
1）如用一般的锅子步骤2继续小火煮到绿豆开了，加入冰糖即可。使用焖烧锅的好处是不用看火，水份挥发较少（所以能保留食物的原汁原味）和节省煤气。
2）绿豆和水的份量只做参考，或多或少依个人喜好调整，一般水份为豆的至少10倍。
3）绿豆可事前用水浸泡以缩短烹煮时间。
4）我用的是2.5公升的焖烧锅，加入绿豆后注入水到大约8分满。焖烧锅要在至少70%满的情况下才能发挥最好的效果。

Green Bean Soup with Purple Sweet Potato (Using Thermal Cooker)

Ingredients:
150g green bean
2 litre water
1 medium size purple sweet potato, cubed (can also use other type of sweet potato)
1 bundle of Pandan leaves, tied into a knot
Rock sugar to taste

Method:
1) Rinse green beans for a few times and remove any bad bean. Add green beans into the inner pot of thermal cooker, add water and bring to a boil over high heat. Add sweet potato, continue to boil for another 10 mins.
2) Remove from heat and place the inner pot into the thermal cooker. Leave it in the thermal cooker till the green beans softened (about 20-30 mins, depending on individual preference and thermal cooker), remove inner pot from thermal cooker, add rock sugar and cook over stove till sugar dissolved. Remove Pandan leaves and serve hot.

Note:
1) If using normal pot, just continue to simmer over low heat till green beans softened in step 2. The benefits of using thermal cooker are no monitoring of fire is required, less loss of water (thus preserves the taste of food) and save gas.
2) The amount of green bean and water is just for reference, feel free to adjust according to individual preference, usually the water amount is at least 10 times of bean.
3) Green bean can be pre-soaked in water to reduce cooking time.
4) My thermal cooker is 2.5 litre. After adding in green beans I added water till about 85% full. Thermal cooker only works well when at least 70% filled.

I am submitting this to Aspiring Bakers # 20 – Asian Dessert Buffet (June 2012), hosted by Moon of Food Playground.