My Sourdough Banana Bread is unlike any banana bread! The sourdough starter is the secret ingredient to fluffy, moist banana bread.
Preheat the oven to 375°F (190°C) and butter and line with parchment an 8-inch (20-cm) square baking dish. Set aside.
In a large mixing bowl, whisk together the bananas, brown sugar, sourdough starter, and vanilla extract.
Add the eggs, one at a time, followed by the vegetable oil and milk, mixing completely before each addition.
In a small bowl, whisk together the flour, baking soda, and salt, then fold into the wet ingredients until just combined.
Pour the batter into the prepared baking dish and bake for 45 to 50 minutes, until the bread is a deep golden brown and a skewer inserted in the center comes out clean.
Let cool in the baking dish for 10 minutes before transferring to a wire rack to cool completely. Serve at room temperature.
Store in an airtight container at room temperature for up to 3 days. For longer storage, freeze for up to 2 months.