Wash the oranges well (I washed them with a brush). Grate the zest on a fine grater, peel it. Grind the zest and pulp in a blender into a puree. Gelatin (if necessary) pour water. Bring the pulp and zest to a boil on the stove, with constant stirring, add starch (previously diluted in water) and gelatin. Bring to a boil (the mixture will thicken). Pour into 2 molds (I have a ladle of 16 cm, I left it in it) and cool in the refrigerator.