Some form of short bread. Ideally Dutch butter cookies but really any shortbread. If that’s unavailable then you know a Rich Tea really is the perfect dunking biscuit.
@ahibbins, no, in a word. Hobnobs and digestives, though still both often have chocolate on the top and look very similar in appearance. The former is made of oaks, the latter isn’t and just made of flour and baking powder.
I appreciate I’m shamefully late to this thread, but just wanted to share that I have perfected a homemade hobnob recipe - equal quantities of butter, muscovado sugar, oats and flour, then bake.
Why make the effort you ask? Try a freshly baked hobnob and I promise you will understand. The ultimate tea-dipper. Also makes the best. crumble. topping. ever.