Now this is what I like to call a shortcut sourdough bread. It is not the strongest sourdough starter so I add yeast to my recipe, but the starter gives a lovely sour taste to the bread. This trick also cuts the rise time!
Combine 1 cup flour, sugar, and dry yeast in the bowl of a stand mixer with the bread hook.
Add warmed milk and fat to bowl, mix well. Mix in the sourdough starter.
Add the salt and flour, a little bit at a time, until you get a slightly sticky ball of dough that sticks together. The quantity of flour will depend on the humidity of your climate.
Knead the dough for 8 to 10 minutes, by hand or in the mixer. It should be elastic.
Oil the mixing bowl and place the dough in it, turning it once to oil the dough. Cover with a damp cloth and rise for 1 hour, or until doubled in volume.
Punch down gently and leave to rest for 15 minutes.
Divide dough in two and shape into 2 loaves. Place on a greased baking sheet and leave to rise, covered, for 1 hour or until doubled in volume.
Lightly slash the bread with a razor blade or sharp knife. Bake in a preheated oven at 375 F for 30-35 minutes, or until a thermometer inserted inside reads 210 F.