How to Make It
Pour the water into a food processor and sprinkle the yeast on top. Add the flour, honey, lavender and salt and process for 1 minute. Add the walnuts and pulse just until they're evenly incorporated into the dough. Scrape the side and bottom of the bowl as needed with a rubber spatula. The dough should be very soft and sticky. Transfer the dough to a bowl, cover and let rise in the refrigerator for at least 12 and up to 24 hours.
On a lightly floured work surface, pat the dough into a 10-inch square. Fold it in half, pat it out a little, then fold it in half again so that you end up with a 6inch square. Cut the dough in half.
Stretch out each piece of dough to a 9-by-4-inch oval. It will look like the sole of a very big shoe. Transfer the loaves to a lightly floured baking sheet. Cover with a dish towel and let rise at room temperature until doubled in bulk, 1 1/2 to 2 hours.
Preheat the oven to 375°. Bake the loaves on the middle shelf for 30 to 35 minutes, or until browned. Cool completely on a rack before slicing.