Cut off the top of the oranges and remove the pulp.
Use a serrated knife for this.
Squeeze the pulp into a purée, then pass through a sieve.
Mix half the resulting pulp with the blood orange purée.
Whip the Debic Parfait to the desired consistency, and add the blood orange purée.
Divide the orange mousse using a piping bag.
Place in the refrigerator.