Squeeze the oranges to extract the fresh orange juice. Use a fine mesh strainer to filter the juice and remove any pulp particles.
After extracting and filtering the juice, measure out 500 ml of orange juice. Take a thick-bottomed saucepan, pour around 400 ml of the juice into it, and add sugar and cinnamon if desired. Heat the mixture over medium heat, stirring occasionally, until it boils.
Meanwhile, in a separate cup or large glass, vigorously mix the remaining orange juice with cornstarch using a fork to dissolve it and ensure there are no lumps.
Once the mixture in the pan boils, add the cornstarch-dissolved orange juice. Cook the Orange Gelo on low heat for about 5 minutes, stirring constantly. The dessert is done when it thickens to a rich cream consistency.
Pour the mixture into individual crème caramel molds or a half-liter mold. Let it cool to room temperature, cover the molds with cling film, and refrigerate for at least 4 hours for the puddings to set.
When ready to serve, gently loosen the edges of the puddings with a knife, then invert the molds onto a plate and remove them.
Decorate the cold puddings to your liking. I used orange slices and fresh mint leaves for decoration.
