Preheat the oven to 350ºF (180ºC) and line a 9X5" loaf pan with a piece of parchment paper and a small amount of baking spray. Set aside.
Add 1 ½ cups of the all-purpose flour, baking powder, baking soda, and salt to a medium bowl. Whisk to combine and set aside.
Add the sugar and lemon zest to a large mixing bowl. Using your fingers, rub the sugar and lemon zest together to create a sandy texture.
Next, add the oil to the bowl of lemon sugar. Whisk to combine.
Then, add the eggs, one at a time, whisking well until each is fully incorporated.
Add the sourdough discard, 2 tablespoons of lemon juice, and vanilla, then stir well to combine. Add the milk and stir again, then set aside while you prep the strawberries.
Add 1 ¼ cups of chopped strawberries and 2 tablespoons of flour to a small bowl. Toss to coat, then set aside.
Add the flour mixture to the wet ingredients, and fold everything together until no dry flour remains (but be careful not to overmix).
Transfer the floured strawberries and the white chocolate chips (if using) to the bowl of batter, and fold them in until they are evenly distributed.
Transfer the batter to the prepared bread pan.
Bake at 350ºF (180ºC) for 50-65 minutes, or until a toothpick comes out clean.
Cool the bread in the pan for 10-15 minutes.