First of all, the answer is no, there is no need to blanch the fennel. Should you blanch fennel for dumpling filling? Fennel is a plant with a distinctive flavor, and it is often used as a condiment. Should I blanch fennel for dumpling filling? Because of this, we don't need to blanch fennel, as this would weaken its original flavor. Should I blanch fennel for dumpling filling? The advantage of not blanching is that the original flavor of the fennel will be retained and it will be more delicious. Should I blanch fennel for dumpling filling?