Cut out the cauliflower core, then cut the stems and florets into manageable pieces. Boil in salted water 15-20 minutes, until tender, but not mushy. Drain and mash coarsely with a potato masher or fork. Add tomato, onion, and seasonings to the mashed cauliflower. Adjust the seasonings to your taste. Pour eggs into the seasoned cauliflower mix and stir everything together. It should be thick, but eggy, like a chunky pancake mix.
Heat up a griddle or a large frying pan. Drizzle a little oil in the bottom of the pan. When it's nice and hot, drop about 1/3 cup of the mixture to make a nice sized patty. Fry till nice and crispy on one side, then flip it over and do the same to the other side.
Note: Once you get the hang of this, you can do the same thing with diced, cooked potatoes or cooked rice.