This thick gel colour is easy to turn into “edible watercolours”. Dab a little colour onto a palette or small plate and dilute it with a few drops of clear high-proof spirit (vodka works well). The more alcohol you add, the lighter and more translucent the shade – just like with watercolour paints. Paint onto dried fondant or set icing with a fine brush; the alcohol evaporates in moments, leaving just clean colour behind. Let each layer dry before adding the next, and feel free to shade from lightest to darkest. Water works too, but it dries slower and the result usually isn't as crisp.

ProGel is gluten-free, suitable for vegetarians and vegans, and carries halal and kosher certification. It won't affect the taste of your bake, so you can add colour without worrying it will change your dessert's character.

Add the colour in small drops and build it up gradually – you can always add more, but you can't take it away. As a guide, 3 g of colour should be plenty for 1 kg of cake and decorations. Keep the tube closed at room temperature, away from direct sunlight.

ProGel Purple – gel food colouring. / Ingredients: glycerol, silicon dioxide, propylene glycol, colours: E122, E133. / E122 (azorubine) may have an adverse effect on activity and attention in children. / Weight: 25 g. / Use: gel colour for colouring fondant, buttercream, marzipan, doughs and other confectionery pastes. Apply in small amounts. / Storage conditions: store closed at room temperature, protect from direct sunlight. / Best before: see packaging. / Suitable for vegetarians and vegans. Gluten-free. Halal and kosher certified. / Country of origin: United Kingdom.