Spread the batter evenly into the prepared pan, and bake for about 25 - 30 minutes, or until the centre is no longer jiggly and a toothpick inserted comes out clean. Do not over-bake.
Blondies can be stored in an airtight container at room temperature or in the fridge for up to 3 days. They also freeze well for up to 3 months. Thaw overnight before serving.
The calories are an estimate only.