Where to buy them? This one is easy, at least it certainly is in the UK. Most Chinese grocers or mini marts will sell them frozen, which retain all of the aroma you want. If you live in a town with a sizeable Asian population, chances are, you will get them fresh. Otherwise, ...
Strain the pandan juice into a bowl or jug and add to the recipe. You can also get a second, lighter pressing of pandan juice by adding another half cup of water. Just like extracting coconut milk. 2. Using whole pandan leaves