Ingredients

• ²/₃ cup stiff levain sourdough starter from fridge
  
• ¹/₃ cup tepid filtered water
  
• 1 cup bread flour, plus additional bread flour approx. 1/3 cup or more
  
• 3 tablespoons good olive oil
  
• 2 teaspoons dried rosemary
  
• ¹/₄ teaspoon fine ground salt
  
• 1 teaspoon coarse salt - kosher is good is coarse sea salt
  
• ¹/₂ teaspoon baking soda, divided
  
• at least one metal cookie sheet or a baker's peel
  
• a baking stone or a second cookie sheet
  
• parchment paper, optional but a lot easier