Preheat oven to 375 degrees. Spray a muffin tin (or two) with baking spray and set aside.

In a large measuring cup whisk together the sourdough starter, heavy cream, canola oil, egg, and vanilla extract until smooth. Set aside.

In a medium bowl, whisk together the flour, sugar, baking soda, powder, salt, and lemon zest. Take 1 tablespoon of this dry ingredient mixture and sprinkle it over 1 ½ cups of the berries, tossing to coat.

Pour the wet ingredients into the dry and stir very gently to combine, folding batter over itself. When a few streaks of flour remain, stir in the coated blueberries.

Using a large portion scoop, divide the batter among the prepared pans. Top each muffin with a few of the reserved blueberries and about 2 teaspoons of the turbinado sugar.

Bake muffins in preheated oven for 20 – 22 minutes, or until tops are domed, beautifully golden brown, and spring back when lightly touched.

Remove from oven and cool on wire rack for ten minutes before removing from muffin tins. Cool until just barely warm before serving.