Preheat the oven to 325°F (160°C)
Slice the apples into small cubes.
In a large bowl, mix together the sugar with the egg, milk, oil, and vanilla extract.
1 1/2 cups soft brown sugar (packed), 1 large egg, 1/3 cup olive oil, 1/2 cup whole milk, 1 tsp vanilla extract
Add the sourdough discard into the mixture.
1/2 cup sourdough discard (or active)
Mix the salt and baking soda with the flour.
2 1/2 cups all purpose flour, 1 tsp baking soda (bicarbonate of soda), 1 pinch salt
Add the flour mixture to the batter. Make sure you incorporate the flour well to avoid any clumps. Don't overmix.
Add the apple cubes to the batter.
3 medium-sized baking apples (approx. 2 1/2 cups)
Pour the batter into a 9"x13" tray lined with parchment paper.