In a medium bowl, add the flour, yeast, and salt. Mix briefly.
In a separate jug, add the milk, water, and butter. Pop it into the microwave for 15-30 seconds or until it’s lukewarm and the butter has melted. Don’t let it get too hot.
Add the wet ingredients to the dry one and mix until you form a dough. The dough will be quite soft and a little sticky. (NOTE: hold back liquid until you get the right consistency of dough). Once the dough has come together, just scrape down the sides of the bowl and cover tightly with cling film. Now let it sit at room temperature for a minimum of 12-18 hours. (If you want to cook your muffins at a later time then pop the dough in the fridge after 18 hours)
The next morning, the dough will have doubled in size. Turn it out onto a floured surface.  Cover with cling film and let it rest for 10 minutes.
You can now roll it out to 2 cm or slightly over an inch in thickness.
Using a 3-inch cookie cutter dusted in flour, cut out circles and fill them with a spoon of sardine and close them well,  transfer them on to a baking tray lined with parchment paper. Any scraps can be re-rolled and made into another muffin.
Cover the muffins with cling film or a tea towel and let it rest for 40-45 minutes. After 45 minutes, the dough circles will have puffed up a little. Proceed to cook!

Cooking the  Muffins:

Heat a large nonstick frying pan over a steady, medium to medium-low heat.
Add the muffins onto to the non stick frying pan and cover with a lid.
Leave at least a 2 inches between each muffin
Cook on this side for about 6-7 minutes with the lid on,
Flip them over and cook on the other side for another 3-4 minutes.
Let the muffins cool down before eating.
These muffins also toast up really well and taste lovely with melted cheese