What does 'set melted sugar' mean?

Question

Oxford dictionaries (at least the lexico.com version of them) have several definitions containing 'set melted sugar' in them:

• https://www.lexico.com/definition/brittle

A brittle sweet made from nuts and set melted sugar.

• https://www.lexico.com/definition/cracknel

A brittle sweet made from set melted sugar, typically containing nuts.

etc.

What does it mean? I mean I understand what a melted sugar is, but what does the 'set' bit add/mean here?

Googling doesn't provide many results except Lexico itself and some crosswords.

Answer 1

Melted sugar is hot. When it cools, it sets hard again, and when it is hard again, it is (or has) set.

So "set melted sugar" is sugar that has been heated, melted, then allowed to cool again and become hard. It is similar to toffee.