Whisk together the milk, flour, yeast and sugar. Once combined add half the water and beat into the batter, continue to add more water until the batter is thick and smooth. Stop adding water once it reaches the consistency of thick cream. Cover with cling film and leave in a warm draft free place until foaming - about 1, up to 2 hours.
Whisk the salt and baking powder into the batter then heat a heavy based frying pan on the stove to hot but not smoking.
Dampen a paper towel with a little oil and grease the base of the pan and a crumpet (or pastry) rings measuring 3 ½"
Place one ring in the heated pan, add enough batter to fill just below the top of the ring.
Cook for five minutes when there should be many tiny holes on the surface and the crumpet is setting. Flip the crumpet over and cook for another two – three minutes.
Repeat with the remaining batter until used up. Rest the crumpets on a wire rack until cool and reheat in a toaster or under the grill before serving.
NOTE: If the batter seeps from under the ring it is too thin, whisk in more flour. If the crumpet is heavy and without holes, the batter is too thick, add more water.
40 minutes 
