Use a blender to puree the tinned cherries, then strain the puree to make sure you have a nice smooth liquid. Place about half of the puree into a small heavy based saucepan with the sugar. Heat gently and stir until the sugar has dissolved. Now bring the mixture to a boil and allow it to boil rapidly for 5 minutes. Use a pastry brush dipped in water to dissolve any sugar crystals that stick to the inside of the saucepan above the syrup.
Meanwhile, place the remaining puree in a small bowl and mix in the powdered gelatine. This will thicken quickly into a solid mass.
When syrup has boiled for 5 minutes, remove from heat and add gelatin mix. Stir it continuously until it has totally dissolved.
Lightly grease an 8x8 inch or similar (it doesn’t have to be exact) with oil spray. I used a slightly larger tray that made the jubes in the pictures thinner. Pour the mixture into the greased tray and refrigerate for 3-4 hours. Once set, the mixture will be springy and stretchy and should pull away from the edge of the tin cleanly.
Sprinkle a large chopping board or a larger baking tray generously with caster / superfine / sanding sugar and carefully turn the mixture out onto the sugared surface. Sprinkle more sugar all over the top and rub in so that the whole thing is coated. Now chop it into squares or strings using a lightly greased knife and coat each in more of the sugar. Allow them to air dry for a few hours or overnight.