Craig Knows His Onions

To know your onions doesn't mean that you're an expert in onions. It simply means that you are intelligent as regards that topic. Bright, the adjective, B-R-I-G-H-T, is to be clever. Astute also means very clever, very intelligent. Another word used to describe people who are very bright is brilliant. So when it comes to biscuits and chocolate, Craig knows his onions. I'm not onion biscuit. But you do know a lot about biscuits.