In a large mixing bowl, combine the flour, salt, baking powder, and sugars. Add the lemon zest and rub it into the flour mixture and break apart any clumps of brown sugar.

In another bowl, whisk the eggs, yogurt, vanilla extract, and sourdough discard until thick and pale yellow. Pour the melted and cooled butter in last and whisk until combined.

Pour the wet ingredients into the bowl of dry ingredients and use a spatula to mix together until most of the flour is hydrated and a few lumps remain.Gently fold about ⅔ of the blueberries into the batter, reserving enough berries to top the muffins later with 4-5 blueberries each.

For tall muffins with domed muffin tops, cover and chill the muffin batter for at least an hour in the refrigerator and up to overnight.

Preheat the oven to 400ºF (204ºC).Line a standard 12-cup muffin pan with muffin liners or tins and butter or spray them with non-stick spray to prevent sticking.

Fill the muffin liners almost to the brim with muffin batter. For even distribution, you can use a large cookie scoop or ice cream scoop.Dot the tops of the muffins with 4-5 reserved blueberries and a generous sprinkle of granulated sugar.Bake for about 23-25 minutes until the tops are golden brown and a toothpick inserted into the middle comes out clean. Cool for five minutes in the muffin pan before transferring to a wire rack to cool completely.