1. Combine the starter, the buckwheat flour, and 100 grams water in a large bowl to make the jumpstarter. Stir, scraping the sides and bottom as necessary, until all the flour is absorbed. Cover with plastic or a damp kitchen towel and let it sit at room temperature for 8 to 12 hours. The jumpstarter will bubble and become quite fragrant. Meanwhile, feed the remaining starter: Add 50 grams each whole wheat flour and water and stir or shake. Cover and return it to the refrigerator.
2. If you’re not ready to cook when the jumpstarter is ready, cover and let it hibernate for up to 24 hours (see “Baking Bread on Any Schedule” on page 89 of Bittman Bread). Allow about an hour for it to come to room temperature before proceeding.
3. When you’re ready to make the pancakes, add the remaining 100 grams water to the jumpstarter along with the 4 grams salt. Stir just to combine, then add the egg and melted butter and stir again more vigorously until almost smooth. Add a little more water if the batter doesn’t pour from a ladle easily; it should. Cover and let the batter sit until bubbly, at least 30 minutes but no more than 2 hours.
4. Heat the oven to 425°F. Fit a wire rack into a baking sheet and keep it handy. Heat a large griddle or skillet (preferably cast iron, carbon steel, or nonstick) over medium heat. When a couple of drops of water skid across the surface of the pan before evaporating, it’s hot enough. Put a film of oil on the griddle or in the skillet. When it’s hot, ladle in enough batter to swirl into a thin layer about 10 inches in diameter.
5. Cook, undisturbed, until the edges are set and bubbles appear in the center of the crepe, 2 to 4 minutes. Adjust the heat as needed; you want there to be some sizzling without burning.
6. When bubbles appear on the surface, carefully slip a long spatula under the crepe and peek to see if it’s brown on the bottom; when it’s ready turn the crepe. Cook the second side until lightly browned, another minute or so. Transfer the finished crepe to a wire rack and repeat until all the batter is gone, stacking them as you go. (You can cook the crepes up to 1 hour ahead of finishing.)
7. To form the galettes, put a crepe on a large baking sheet, bubble side up. Scatter the center with some cheese and ham and crack in an egg. Fold in the edges to partially enclose the fillings and repeat with the remaining crepes, using a second baking sheet if you need more room. Transfer the pan (or pans) to the oven and bake until the cheese melts, the egg whites become opaque, and the yolks are as runny as you like them, 5 to 10 minutes. Serve right away.

— Recipe developed by Kerri Conan