A quick, easy way to use up your sourdough discard, which I always hate to throw out. I got this from the King Arthur website and we love it. You can use proper English muffin rings or clean tuna cans with the bottoms cut out.
Measure out 1 cup of sourdough discard into a small pitcher or bowl (a pitcher makes it easier to pour the batter).
Mix in sugar and salt.
Grease a skillet and heat over medium-low burner. About the same heat you use for pancakes. Place thoroughly greased rings or cans in skillet.
When skillet is hot, stir in baking soda and immediately pour 1/4 inch of batter into each ring.
Cook until edges appear dry and bubbles have formed.
Remove rings with pliers or tongs and, if desired, flip crumpets and cook for an additional 30 seconds or so.
Stir batter before pouring the next round. You'll need to re-grease your rings and skillet if you do more than two rounds of crumpets (depending on how many rings you have and how quickly you use up the batter).
Enjoy hot with butter and/or jam. Leftovers are good toasted.