Sourdough Focaccia with Crispy Garlic & Rosemary

Name: Sourdough Focaccia with Crispy Garlic & Rosemary
Prep time: 1 h
Cook time: 20 min
Total time: 1 h 20 min
Cuisine: European, Italian, Mediterranean
Ingredients: 8 oz active sourdough starter (1 cup, 100% hydration); 10 oz warm water (1 1/4 cups); 2 1/2 oz whole wheat flour (1/2 cup); 12 1/2 oz unbleached all-purpose flour (2 1/2 cups, see note); 1 1/2 teaspoons table salt; 2 oz olive oil (1/4 cup); 1 head garlic (peel & mince the cloves); 1 scant tablespoon roughly chopped fresh rosemary (from about 1 large or 2 small sprigs); 1.5 teaspoons flaky sea salt