Remember, the longer the sponge sits, the stronger the sour flavor will be. As I was planning to use some of the bread for sandwiches and the rest in garlic bread, I only had it sit for 24 hours.
1 cup sourdough starter
1 1/2 cups warm water
2 tablespoons sugar
3 cups bread flour
1 teaspoon active dry yeast
1/4 cup warm water
2 teaspoons salt
1/2 teaspoon baking soda
3 to 3 1/2 cups bread flour
Combine all the ingredients for the sponge together in a large bowl. Cover with plastic wrap and set on the counter to stand at room temperature for at least 24 hours and as long as 48.
When ready to begin, put the yeast in the warm water and allow to proof for 5 minutes. Place the sponge, the salt and baking soda in a stand mixer with the paddle attachment and stir. Add in the yeast and continue stirring until well mixed. Add one cup of bread flour and mix until incorporated. Trade to the dough hook and add another cup of bread flour. Once incorporated, add another cup of bread flour. You want the dough to only be slightly sticky. Add the final half cup of dough, if necessary. Knead on medium for 8 to 10 minutes.
Let the dough rest for 15 minutes. Divide in half and shape into a rectangle. Roll up and set into lightly greased dough pans. Cover and let rise for an hour or until doubled in size. Use a sharp knife to make diagonal cuts in the top.
While the bread rises, preheat the oven to 375 degrees F. Place a pan of warm water on the bottom rack. Bake the loaves from 35 to 45 minutes or until they sound hollow when tapped. Remove from pans and let cool on wire racks.
To make garlic bread, I roasted 8 cloves of garlic in a little olive oil. Once cool, I then mixed them with a softened stick of butter. I cut the baguette lengthwise and then smeared butter over both sides. Putting the loaf back together, I smeared the remaining garlic butter over the outside bottom and top before wrapping in aluminum foil and baking for 15 minutes at 350 degrees. I removed it from the oven, turned the broiler on high and opened the loaf, so the interior could toast about 4 minutes total.