1. Preheat oven to 350°F (175°C) and grease a 9×5-inch loaf pan with parchment paper.

2. In a bowl whisk sourdough starter, melted butter, sugar, eggs, lemon juice, lemon zest, milk, and vanilla until smooth.

3. Sift flour, baking powder, baking soda, and salt in a separate bowl.

4. Gently fold dry ingredients into wet ingredients until just combined, avoiding overmixing.

5. Pour batter into prepared pan and bake for 45–55 minutes until golden and a toothpick comes out clean.

6. Cool loaf in pan for 10 minutes then transfer to a wire rack to cool completely.

7. In a small bowl whisk powdered sugar with lemon juice (and optional zest) until smooth and pourable.

8. Drizzle glaze over cooled loaf and let set for 15–20 minutes before slicing.

9. Slice into 10 pieces and serve with fresh berries or tea.