Peel the potatoes and onion and finely grate. If using a food processor use the grater attachment. Which ever one you use you want to make sure that there are no lumps left.
Transfer the grated vegetables into a tea towel. Lift up the four corners and twist the towel squeezing as much liquid out as possible. Soggy vegetables means soggy pancakes!!
Transfer the grated vegetables to a mixing bowl and add the eggs, flour, salt and pepper and thoroughly mix together. If you are using cayenne as well then add it now.
Place a large frying pan over a medium heat and add the vegetable oil.
When the oil is hot, add a spoonful of the mixture to the pan gently spread it out a little to the size and thickness you want.
Fry for about 2 minutes each side or until the pancake is crispy and brown depending on how thick you have them.
When cooked transfer to kitchen paper to drain and oil and serve with toppings of your choice.