Stir sugar into warm water and sprinkle with yeast.
Let stand 5 minutes or until the surface is frothy.
Stir gently to moisten any dry particles remaining on top.
Place half the flour in a large bowl.
Add yeast liquid to flour with starter dough, combining to make a dough.
On a floured surface, knead dough until smooth.
Cover and let rise at room temperature overnight.
Lightly broil bacon.
Drain on paper towels; chop very finely.
Cool.
Preheat oven to 400°F (205°C).
Mix salt, 2 teaspoons caraway seeds, bacon and remaining flour into dough.
Knead until smooth.
Sprinkle baking sheets with flour.
Divide dough into 6 equal pieces.
On a floured surface, roll out dough thinly into flat cakes 10 to 12 inches (25 to 30 cm) in diameter.
Brush tops with water; cut crisscross markings.
Sprinkle with remaining caraway seeds and sea salt.
Place on floured baking sheets.
Bake 30 minutes or until brown.