Add your chosen fruit and juice to the blender and puree until completely smooth. I always run mine for a full minute longer than I think it needs, because any leftover chunks will clog your molds later. If you're using frozen fruit, let it thaw slightly first so the blender doesn't struggle.
Pour the fruit puree into your saucepan and sprinkle the gelatin evenly over the top. Let it sit for a minute or two so it "blooms," which just means it softens and absorbs liquid. This step is what keeps your fruit snacks from turning out grainy or clumpy once they set.
Place the saucepan over low heat and whisk constantly until the gelatin fully dissolves into the puree. This only takes a few minutes, and you want to avoid boiling it, since high heat can weaken gelatin's setting power. The mixture should look glossy and completely smooth.
Remove the pan from heat and stir in your honey and vanilla extract. Taste the mixture here and adjust sweetness if needed, since fruit sweetness varies a lot by season. This is also the stage where I add any optional citric acid for a tangier bite.
Carefully pour or drop the warm mixture into your silicone molds, filling each cavity close to the top. Working quickly matters here because the mixture starts thickening as it cools, making it harder to pour neatly.
Transfer the filled molds to the refrigerator and let them chill for 20 to 30 minutes, or until firm to the touch. Once set, gently pop each fruit snack out of its mold and they're ready to enjoy or store.