Mix together cooked rice, onion, Cheddar cheese, egg, garlic, salt, red pepper flakes, black pepper, parsley, and onion powder by hand in a large bowl until well combined. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes.
From rice mixture into 4 small patties.
Heat oil in a large skillet over medium-high heat. Fry patties in hot oil until lightly browned, about 5 minutes per side.
