How to turn a double-door kitchen cupboard into a safe

If you have at least two children and if they are not very young anymore, sometimes [delicious] things will disappear from the kitchen, which were actually intended for the preparation of a meal.
Of course, none of the kids admits they've eaten the *sweet*. It can only have been the respective sibling. And -of course- they already learned to lie ... without blushing.
Consequently, you can only lock things away if you want to ensure their later availability.

There are certainly various ready