Put both flours into the bowl of a stand mixer and add in the yeast.
Dissolve the sugar in the warm milk, then pour this into the flour mixture.
Beat the mixture until you have a smooth batter. This will take three to four minutes and is hard work because the mixture is stiff, but it is essential to develop the protein strength in the batter and will ensure the crumpets develop their characteristic holes as they cook.
Cover the bowl with cling film or a tea towel and leave to stand for about an hour. The mixture will rise and then begin to fall you will see marks on the side of the bowl where the batter reached before it dropped.
This indicates that the yeast has created its carbon dioxide and is now exhausted. The gluten will now have developed sufficiently to give the crumpets structure and enable them to rise and hold their shape.
Mix 150ml of the tepid water with the bicarbonate of soda and salt. Stir this liquid into the batter until evenly combined, then gradually stir in as much of the remaining water as you need to get a thick dropping consistency.
Cover the bowl and leave the batter to rest for about 20 minutes. Little holes will appear on the surface and the batter will become a bit sticky.
Heat a flat griddle pan or heavy-based frying pan on a medium-low heat. Lightly but thoroughly grease the inside of at least four 7cm to 8cm metal crumpet rings (ideally non-stick).
Lightly grease the griddle or pan, using a crumpled piece of kitchen paper dipped in oil.Its a good idea to start with a trial crumpet. The first one is never the best, like the first pancake.
Put a greased crumpet ring on the griddle. Ladle enough batter into the ring to come just below the rim. The temperature of the pan is important: it is better to cook the crumpet lower and slower than hot and fast.
After six to eight minutes, the bottom of the crumpet should be browned and the rest almost cooked through. You’ll know when it is nearly ready once the top looks almost set and most of the bubbles that have formed on the surface have burst.
You can slightly speed up the cooking by popping these bubbles as they appear, using the sharp tip of a knife. When the crumpet is ready, the bubbles will stay open rather than fill up with liquid batter.
Turn the crumpet over carefully, using two kitchen tools, such as a spatula and a palette knife. Leave the crumpet to cook for another minute or two, then lift it off the griddle onto a wire rack.
Remove the ring, if it sticks, run a small, sharp knife around the outside of the crumpet to loosen it.
Now that you have fine-tuned the time and temperature needed for your batter, you are ready to cook the rest of the crumpets in batches.
Serve the crumpets straight away, split or whole, with plenty of butter. Alternatively, leave them to cool on the wire rack and toast them before enjoying with butter.