Heat a tablespoon of vegetable oil in a small frying pan over a medium-high heat. Toast the cumin and coriander seeds in the oil for around a minute until they begin to take a little colour.
Pour the toasted seeds into a food processor. Add the prepped onion, garlic, red chilli and ginger. Pour in the lime juice and soy sauce and blitz until the vegetables are a rough paste.
Peel the celeriac, removing any of the gnarly root exterior. Chop the celeriac into large but manageable piece and grate them into a large mixing bowl. Season with a little salt and cracked black pepper.
Pour the chilli onion paste into the mixing bowl with the celeriac. Tip in the gram flour and plain flour. Combine all the bowl contents using your hands. Once incorporated the celeriac mixture should be sticky and malleable.
Ready a large oven tray or chopping board. Then, using your hands, take a little of the celeriac mixture and shape it into a palm sized patty. Place the finished patty onto the waiting tray. Repeat until you have about 8 - 10 good sized patties.
Select in a pan in your kitchen which you can shallow fry your fritters in. Ideally you want a pan that is wide enough to fry about 4 patties at a time and deep enough to hold a layer of oil about half the thickness of your patties. I like to use a saute pan - but a deep frying pan or traditional saucepan will also do.
Heat a good layer of vegetable oil in the chosen pan. As stated, the oil layer should be enough to coat about half the thickness of the celeriac patty. This is normally about 200ml, but can vary depending on your pan. Add a small piece of celeriac fritter to the pan whilst it is heating up. Once the piece starts to bubble and move around the oil fish it out using a slotted spoon - your oil is now hot enough to fry in.
Add a few fritters to the hot oil. (You don't want to crowd the pan with celeriac patties. I normally do about 4 at a time - which allows for a good amount of space between the patties.) Fry the fritters for 5 minutes on each side or until golden and crispy. Once cooked, remove and reserve on a oven tray until all the fritters are fried.
Serve the fritters immediately. Alternatively, you can keep them hot in the oven until needed.