18g(2 x 9g sachets) lite (no sugar) jelly crystals (you can use any flavour you like - we used strawberry and it looked and smelled amazing. From the original blog post it seems you can use regular jelly crystals if you can’t get the low/no sugar kind but it will result in a stickier, messier slime)
Combine the cornflour and jelly crystals in a medium sized mixing bowl.
Add about ¼ cup water and mix.
Gradually add more water until it reaches a consistency you are happy with.