Combine the bicarbonate of soda and citric acid in a large bowl.

Add a few drops of your essential oil* and stir well.

Stir in some cosmetic glitter if you are using it.

Carefully add your colour a drop or two at a time, combining well with each addition until you get your desired colour. You must do this gradually to avoid the fizzy reaction between the bicarb and the citric acid from happening in your bowl rather than your bath!

Once you are happy with colour and scent you can begin to add water. Once again it is important to do this gradually. The mister means that you aren’t adding water too quickly to one part of your mixture and setting off the reaction.

Stir after each addition.

Your bath bomb mixture is ready when it will just hold together when pressed in your hand. It mustn’t feel damp and it is far better for it to be too dry and not work in your moulds at first than too wet. You can always add a bit more water, you can’t take it away!

Press your bath bomb mixture into your mould, one half at a time. Pile extra mixture into each half so that it is overflowing and then press the two halves together firmly brushing away the excess as it crumbles out.

Carefully remove one half of the mould and then the other and gently place your bath bomb into your pie tray.

Leave to dry and firm up.