1. Lightly grease your silicone gummy molds or a small baking dish with neutral oil or nonstick cooking spray, wiping away any excess so there is only a thin, even coating.

2. Pour 1/2 cup of the cold fruit juice into a small saucepan and sprinkle the unflavored gelatin evenly over the surface. Let it sit undisturbed for 5 minutes so the gelatin can bloom and fully hydrate.

3. Add the remaining 1/2 cup fruit juice, the granulated sugar or honey, and the lemon juice to the saucepan with the bloomed gelatin.

4. Place the pan over low heat and cook, stirring constantly, until the sugar and gelatin have completely dissolved and the mixture looks smooth and glossy, 3 to 5 minutes. Do not let the mixture boil.

5. Remove the pan from the heat and, if desired, stir in the citric acid a pinch at a time, tasting carefully until the gummies are as sour as you like.

6. Transfer the warm gummy mixture to a heat-safe measuring cup or small pitcher with a spout to make pouring easier.

7. Carefully pour the mixture into the prepared gummy molds, or pour it into the greased baking dish to make gummy cubes. Skim off any bubbles on the surface with a spoon.

8. Place the filled molds or baking dish on a tray and transfer to the refrigerator. Chill for at least 1 hour, or until the gummies are completely firm and springy when gently pressed.

9. Once set, pop the gummies out of the molds, or cut the slab into small cubes if you used a baking dish.

10. Store the gummies in an airtight container in the refrigerator for up to 7 days, serving them chilled for the best chewy texture.