Step 1

Preheat the oven to 350 degrees Fahrenheit and generously grease and line a loaf pan.

Step 2

In a large mixing bowl, beat the sugar, lemon juice and zest, and butter for about one minute. Add the eggs, avocado oil, vanilla, and milk. Beat again until just combined.

Step 3

Using a wooden spoon, stir in the sourdough discard until combined.

Step 4

In a separate bowl, whisk together the flour, salt, and baking powder. Pour into the wet ingredients and fold until everything is just incorporated. Do not over mix.

Step 5

In a small bowl, toss the blueberries with the ½ tablespoon of flour until completely coated. Fold the flour-coated blueberries into the batter.

Step 6

Pour the batter into the prepared loaf pan.

Step 7

Make the crumble by combining all of the ingredients in a bowl. Spread the crumble mixture over the top of the loaf evenly.

Step 8

Bake for 60-70 minutes or until a toothpick is inserted and comes out clean or with just a few moist crumbs. Begin checking at the 50 minute mark.

Step 9

Let cool for 20 minutes in the pan before carefully transferring to a wire rack to finish cooling for another 40 minutes before slicing and serving.