I promised a friend I'd post this recipe as an example of how to use sourdough starter. If you're new at bread baking, focaccia is great way to start because it's pretty forgiving. It's also well suited to long, slow, fermentation at room temperature or below, which is handy if you don't have a proofing box (used by bakers to keep the dough warm while it rises). The only thing it's not well-suited to is people who are in a hurry. But that's true of almost any yeast bread.
If you don't know what a sourdough starter is, or how to make one, stay tuned, I will post something soon. And trust me, you will like it, even if you're not from Alaska. Once upon a time all bread was made this way.
SPONGE
2 cups white starter (should be about like pancake batter, but lumpier, maybe a tad thicker)
1 cup warm water (not hot, just warm)
1 packet (1/4 oz) dry-active yeast (or less, see below)
1 tablespoon honey
1 tablespoon olive oil
DOUGH
2 teaspoons salt
4 cups bread flour
TOPPINGS (OPTIONAL)
Carmelized onions
Parmesan cheese
Olive oil
Fresh basil and thyme
Salt and pepper
1. Create a sponge by mixing the first 5 ingredients (starter, water, yeast, honey, and olive oil). Set it in a cool place (ie, not on the oven or in direct sunlight) to ferment until bubbly, maybe 30-40 minutes. The idea here is jump-start the yeast by giving it a nice warm sugary solution to feed on. If you see bubbles, you know the yeast is on its way. Personally I use a bit less than the full packet of yeast because I like a slow fermentation (rise). If you're a purist and you have a very active starter, you can skip the commercial yeast altogether.
2. Add the 2 remaining ingredients (salt and flour) and mix until a dough forms. If your mixer has a dough hook attachment, use that. Otherwise you can knead by hand, although the dough may be a little wet to be easily workable. Work the dough until it is smooth and elastic in your fingers, about 6-8 minutes. Shape the dough into a smooth ball, set the ball in a clean mixing bowl, drizzle on a bit of olive oil, and cover with plastic wrap to keep it from drying out.
3. Set the dough in a cool place and let it ferment (rise) until it doubles in size. This may take 4-6 hours or longer, depending on the local temperature, the amount of yeast you used, and how active your starter was to begin with. Be patient.
4. Line a half sheet pan (12" x 17") with parchment paper and brush or spray with olive oil. (If you don't have parchment, you can try lining the pan with thin layer of corn meal, but parchment is recommended.)
5. Punch the dough once or twice to force out the air, and set it in the sheet pan. Use your fingers to gradually spread the dough to fill the pan out to the corners. If it doesn't want to spread all the way immediately, let it rest a few minutes and try it again.
6. Cover the dough with plastic wrap again (you can use the same piece you used before) and let it rise until it bulges out of the pan.
7. Dimple the dough with your fingers, basically pressing in every inch or two to make a bunch of holes. The holes add to the surface area, adding texture and visual appeal. They also tend to fill up with any toppings you add, creating little pockets of flavor.
8. Let the dough rest a bit longer. This is called benching, and allows the gluten proteins in the dough to relax. (More on gluten in another post.)
9. While the dough benches, preheat your oven to 400°F.
10. Top the dough as desired (see below) and bake until golden on top and crispy on the bottom. Remove from the pan immediately, and cool.
Toppings
Topping a focaccia is an art in itself. You can go minimal, brushing with a bit of olive oil, salt, and pepper, or you can pile on the toppings to produce what amounts to a thick-crusted pizza. Personally I like enough topping to add interest, but I want bread, not pizza. My favorite version is to brush the doubh with olive oil just before baking, followed by some tomato paste (thinned with more olive oil to make it easier to spread). Season with thyme, salt and pepper, and add a thin layer of carmelized onions (two large onions cooked until nicely browned). Bake for 10 minutes, then add a layer of parmesan cheese, and return to the oven until done. Finally, garnish the finished bread with a bit of shredded basil.
And finally, as an alternative method to slow the fermentation even more, you can set the dough in the refrigerator overnight after step 2 above. This is called retarding the dough because the cold will slow the yeast to a crawl, allowing even more flavor to develop. The next day, remove the dough and continue from step 3. (It may take a while to rise at that point because it will need to warm up first.)