Pour the 1/2 cup of cold fruit juice into a small saucepan and sprinkle the 2 1/2 tablespoons of unflavored powdered gelatin evenly over the surface. Let this mixture sit for 5 minutes until the gelatin absorbs the juice and looks like a thickened, lumpy paste.
Turn the stove to low heat and gently warm the gelatin mixture, stirring constantly with a whisk or a rubber spatula for about 2-3 minutes. Continue until the gelatin is completely dissolved and the liquid is smooth with no visible granules.
Whisk the 1/3 cup of honey into the warm liquid until it is fully incorporated and the mixture is smooth.
Lightly coat an 8x8 inch baking dish or a silicone mold with cooking spray, then carefully pour the liquid gelatin mixture into the prepared dish.
Refrigerate the dish for at least 3 hours, or until the gelatin is completely firm and set. It should feel solid to the touch and pull away from the edges of the dish slightly.
Once fully set, run a thin knife around the edge of the dish to loosen the sheet of gummies. Turn it out onto a cutting board and cut it into small squares using a sharp knife or use small cookie cutters for fun shapes.