Combine focaccia dough ingredients: 100g active sourdough starter, 375g water, 500g bread flour, 10g salt.
Prepare topping: 2 fresh peaches, diced.
Make cinnamon streusel: 1 cup all-purpose flour, 2 tbsp brown sugar, 2 tsp cinnamon, ¼ tsp nutmeg, 4 tbsp melted butter.
Make brown butter vanilla glaze: 4 tbsp butter, browned, 1 cup powdered sugar, 1 tsp vanilla extract, 1–2 tbsp heavy cream, Pinch of salt.
Add more heavy cream until desired consistency is reached for the glaze.
