Warm the milk and water in a jug to around 35C in the microwave - this will take 45 seconds to 1 minute depending on the wattage of your microwave (ours is an 800W). Add the yeast and sugar, stir and let them dissolve. Set aside for 10 minutes, or until frothy.
Sift the flour, baking powder and salt into a large mixing bowl, make a well in the centre and pour in the yeast mixture.
Whisk until you have a smooth batter (like the consistency of thick yogurt or double cream).
Cover the bowl with a damp towel or cling film and leave in a warm place for 45 minutes, or until bubbles have formed on the surface.
Grease 2 crumpet or egg rings (9cm diameter) and lightly grease a non-stick frying pan and place it over a medium heat.
Put the greased rings in the pan and when hot, spoon 4 tbsp of mixture into each ring and cook for 5 minutes, or until little bubbles appear on surface.
Once the bubbles have burst leaving small holes over the surface use tongs to remove the egg rings. Flip the crumpets over and cook for 1 minute on the other side. Repeat until the mixture is finished (around 10 crumpets), greasing the rings and pan as needed. Enjoy for breakfast or brunch.