Begin by pouring your chilled heavy cream into a large mixing bowl. Using an electric mixer, whip the cream on medium speed until it forms soft peaks, about 3-5 minutes. Set aside to prevent deflation.

In a small saucepan, pour half a cup of fresh orange juice and sprinkle the gelatin over the top. Let it sit for about 5 minutes to bloom. Gently heat over low heat, stirring constantly until fully dissolved, about 2-3 minutes.

Remove the saucepan from heat and stir in the sugar, orange zest, and the remaining fresh orange juice. Mix until sugar is dissolved, then let the mixture cool slightly.

Gently fold the cooled orange mixture into the whipped cream using a spatula, being careful not to deflate the cream until fully combined.

Spoon the mousse mixture into serving dishes, cover with plastic wrap, and refrigerate for at least 4 hours, preferably overnight.

Once set, remove from the refrigerator and garnish with fresh orange slices, mint leaves, or a sprinkle of zest if desired. Serve chilled.