A 'cruffin' is a pastry hybrid of croissant and muffin — flaky laminated dough baked in a muffin tin, often filled with cream or jam. Invented in Melbourne around 2013 and popularised globally by San Francisco's Mr. Holmes Bakehouse. If your teen wants to try a cruffin, they are after a trendy pastry. Harmless. Note the slug 'croissant-laminated' simply describes the technique that defines it.