These are quite possibly the best thing I've ever made from my sourdough starter, and by far the quickest and easiest. Crumpets are my most favorite storebought baked item - they are soft & chewy with big, open holes on the top for the butter and honey to seep into. They are wonderful, and I had almost given up hope of making my own when I happened across this old recipe on the King Arthur website. 
It worked like a charm!
- For this batch I mixed 1 1/2 cups of my leftover 100% hydration starter (right out of the fridge where I'd been collecting it every time I made bread) with 1.5 teaspoons white granulated sugar, 3/4 teaspoon baking soda, and 3/4 teaspoon salt. Almost immediately, it gets very, very bubbly.
- I poured the batter into 3.5" crumpet rings on my pancake griddle in a big dollop that slowly spread to fill the rings about 1/4 inch deep before rising.
- I only have 4 crumpet rings, so once the sides started to set, I removed the rings and poured 4 more while letting the first ones cook until there were lots of bubbles on top and the sides were getting dry.
- I flipped them briefly, and took them off the griddle.
- I ate some hot right off the griddle (soooo good), and heated the rest up the toaster later on.
- To serve them, spread with butter and honey and watch them disappear into the holes, saturating the crumpet with buttery goodness. They are not crispy like english muffins.
- 1 1/2 cups starter made 12 crumpets.
I have since tried this recipe with freshly fed sourdough starter, with less luck. It seems to work best with the old leftovers I collect in my fridge over several weeks. I also tried a half whole wheat version, but the texture just isn't the same as with 100% white flour.
I'll be making these again!