In a large mixing bowl, combine the flour, salt, baking powder, and baking soda. In a separate bowl, add the lemon zest and sugar. Stir together, pressing the zest into the sugar so the oil is absorbed.
To the sugar mixture, whisk in the eggs, oil, vanilla, buttermilk, and sour cream until combined.
Add the flour mixture to the wet ingredients and stir. There should not be any lumps.
Toss the blueberries in a tablespoon of flour, then fold them into the muffin batter using a rubber spatula.
Fill the muffin liners 3/4 way of the way full.
Sprinkle the top of each muffin with extra blueberries.
Bake for 18-20 minutes. Allow the muffins to cool in the pan for 5 minutes, then transfer them to a wire rack to finish cooling.
If desired, drizzle with a lemon glaze and serve!