Gently peel and segment the fresh mandarin oranges, reserving some for garnish.

Blend the majority of the mandarin orange segments with the unsweetened orange juice until smooth.

Strain the blended mixture through a fine-mesh sieve for an ultra-smooth jelly.

In a medium heatproof bowl, sprinkle gelatin powder over cold water and let it bloom for 5-10 minutes.

Pour boiling water over the bloomed gelatin and whisk until dissolved completely.

Combine the dissolved gelatin with the strained mandarin orange mixture, add erythritol and salt, whisk until sweetener is dissolved.

Pour the mixture into an 8x8 inch baking dish or individual ramekins.

Chill for at least 4 hours or until set, preferably overnight.

Garnish with reserved mandarin orange segments before serving.