Gather all your ingredients so that you have everything close at hand on the counter or table.
Prepare the Dough
In a large mixing bowl, combine active sourdough starter, warm water, molasses, caraway seed, instant yeast, kosher salt, and ground cardamom.
Stir in dark rye flour plus 1 cup of the all-purpose flour.
Turn dough out onto a lightly floured surface and begin kneading the dough, adding in the remaining flour as needed to make a nice firm dough. Knead for 5-6 minutes until dough is smooth and elastic. (If desired, you may use an electric mixer and knead with dough hook for the same amount of time.)
Place dough in a large greased bowl and cover with plastic wrap. Allow to rise until it has nearly doubled, about 1.5-2 hours.
(If you opt not to use the instant yeast, you’ll want to go through a stretch and fold process of the dough during this rising time, about every 40-45 minutes.)
Form Loaves
Gently deflate the dough and shape into one large round loaf or two smaller loaves. Place on a sheet of parchment paper and cover with plastic wrap that has been sprayed with baking spray.
Another option at this point, is to form the dough into an oblong loaf and place it in a greased loaf pan. For this recipe you could use one oversized loaf pan or a Pullman loaf pan. Or 2 standard loaf pans or even a cocktail sandwich loaf pan. Cover and allow to rise until nearly double. Bake in 400℉ oven on a middle rack for 30-35 minutes until baked through.
Allow the dough to rise for 60-90 minutes, until nearly doubled. Place baking stone on a middle oven rack and preheat oven to 400℉.
Prepare Loaves for Baking
When ready to bake, make two slits crisscrossed on the top of each loaf.
In a small bowl, whisk together 1 medium egg and a tablespoon of water to make an egg wash. Brush the top of each loaf with egg wash and sprinkle with bread seasoning mix, such as Everything Bagel. (This step is optional.)
Spritz the loaves with water. Using a pizza peel, slide loaves on parchment paper onto the hot baking stone.
Bake in a preheated oven for about 25-30 minutes, until nicely browned and internal temperature tested with a digital thermometer reaches 205-210°F. (Or test for doneness by tapping your knuckle on the top of the loaf. If it has a hollow sound, the bread should be fully baked.)
Remove loaves from oven and cool on a wire rack. Makes 1-2 loaves that will serve up to 16 people.