Step 1: Begin by blooming the gelatin. Sprinkle the 2 tablespoons of unflavored gelatin powder evenly over 1/2 cup of cold water in a medium-sized heatproof bowl. Let it sit undisturbed for 5-10 minutes to allow the granules to absorb the water and swell.
Step 2: In a small saucepan, combine 1.5 cups of water, your chosen natural sweetener, and the mashed or blended pink fruits. Bring this mixture to a gentle simmer over medium heat, stirring occasionally, until the sweetener has fully dissolved and the fruit has infused the liquid with color and flavor. Do not bring to a rolling boil.
Step 3: Remove the saucepan from the heat. Pour the hot fruit-infused liquid over the bloomed gelatin in the heatproof bowl. Stir continuously with a whisk or spoon until the gelatin is completely dissolved and the mixture is clear and smooth, with no lumps remaining.
Step 4: Stir in the remaining 1 cup of cold water and the fresh lemon juice (if using) into the gelatin mixture. This helps cool down the mixture and adds a touch of brightness. Pour the mixture carefully into individual serving dishes or a large, shallow glass container. Cover loosely and refrigerate for at least 4 hours, or preferably overnight, until the gelatin is fully set and firm to the touch.