Steam or boil cauliflower florets until tender, then drain well and mash until smooth.
In a large bowl, combine mashed cauliflower, cheddar, Parmesan, eggs, breadcrumbs, green onions, garlic, salt, and pepper.
Form mixture into small patties using your hands.
Heat olive oil in a skillet over medium heat.
Cook patties for 3 to 4 minutes on each side until golden brown and crisp.
Transfer to a paper towel-lined plate to drain excess oil and serve warm.