Slice just one of the carambola fruits and place a single star-shaped slice into the bottom of each section of a (greased) petit four tray. Puree the remaining two carambola fruits with ½ cup of water. In another bowl, place cream butter and sugar. Add eggs one at a time, mixing after each addition until well combined. Add flour and carambola puree and beat until smooth. Spoon batter evenly into petit four tray, and bake at 180°C for 15-20 minutes or until a skewer comes out clean. Turn out and cool on a wire rack.