The product illustrated is a box of ingredients for making a lemon meringue pie. It was produced by Greens, a company which started selling mixes in Brighton in the early years of the 20th century.
The intention of the manufacturer was to simplify home baking by including all the ingredients, apart from one egg. Full instructions were displayed on the box, which also gave an idea of the equipment and utensils that would be needed.
Using the mix would have been time-saving and required less skill than starting from scratch, following a traditional recipe.
This particular mix is no longer produced and has been superseded by a version which is just for the pie filling. The box shows this one had an expiry date of September 1989.
Dessert mixes currently produced by Greens include tiramisu, egg custard, chocolate mousse, cheesecake, blancmange and jelly.