The night before preparing,remove sourdough starter jar from fridge and let sit at room temperature.
In the morning, once the starter has risen a couple of inches, remove one cup from the jar and set aside; feed the remaining starter with one cup all-purpose flour and 1/4 cup warm water and stir, then replace starter jar to the fridge.
If the starter has not risen, may be dormant and require a feeding first, or more time to aerate. Make sure the starter can breathe (I use a rubber band and a piece of cheesecloth over the top of the jar- no tight lids please). Also make sure your starter has enough room in the jar to grow after feeding- you can take some off and dry it in a dehydrator and store it (this is known as putting it to bed).
Take the cup of starter you removed and mix it with the milk, flour, egg, baking soda, baking powder, salt and melted butter (cooled dowuntil it comes together, but do not overmix.
Heat a griddle to moderate and lightly oil.
Drop batter by 1/4 cup measure onto griddle (I use a #16 disher/ice cream scoop- if you aren't sure of the size, test it by filling the scoop with water and measure).
When pancakes have lots of holes and seems somewhat dry looking, flip the pancakes and cook the other side.
Keep pancakes warm while you do the remainder. You can keep them on a cookie sheet- most times I don't keep in oven but will just nuke them if they got cold while waiting.