I've been playing around with the firm starter from Maggie Glezer's "Artisan Baking" book with good recipe results, so I decided to replace the dry yeast in Jim Lahey's no knead bread with about 12 grams of starter. The starter was dissolved in water before it was added to the flour.
After the overnight rise, I folded and shaped the dough and let it have the second proof in a floured banneton. Instead of baking it in a covered pot, I turned the dough out on a parchment covered peel, slashed it and let it bake on the parchment, on a stone under a presoaked clay lid which heated up with the oven. After 30 minutes, the lid was removed and the loaf baked for 15 minutes more.
The result is delicious. The flavour is not sour at all, but much fuller than when regular yeast is used. The crust, crumb and rise are perfect. It's a very simple change on a very simple recipe. I love that such a low effort gives such a great loaf of bread and just wanted to "spread the word".