Recently, I was at a dinner party which included a gluten-free guest; so naturally, I made a potato-based lemon drizzle cake. The results, which were surprisingly fluffy and delicious (the BBC recipe it’s based on has five-star reviews, or I’d never have risked it), surprised me. But on my way home, I had a last-minute panic ― hang on, I thought, the dense, heavy cake used a LOT of baking powder. Is that gluten-free? And how is it even made?The offending articleIs baking powder gluten-free?Some news from Dr Oetker prevented me from sending a post-party alert; it’s “naturally gluten-fr