Preheat and prep: Heat your oven to 375°F (190°C).
Line a 12-cup muffin tin with paper liners or lightly grease with oil.
Mix dry ingredients: In a large bowl, whisk 1 3/4 cups whole wheat pastry flour, 1/4 cup rolled oats (optional), 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon fine sea salt, and 1/2 teaspoon cinnamon.
Combine wet ingredients: In a separate bowl or large measuring cup, whisk 3/4 cup plain Greek yogurt, 1/2 cup milk, 1/3 cup olive oil, 1/3 cup maple syrup, 2 large eggs, and 1 teaspoon vanilla. Add 1 teaspoon lemon zest if using.
Make the batter: Pour the wet mixture into the dry ingredients. Stir gently with a spatula until just combined.
The batter should be thick but scoopable. Do not overmix.
Add blueberries: Fold in 1 1/2 cups blueberries. If using frozen, toss them first in 1 teaspoon flour to reduce color bleed, then fold in quickly.
Fill the tin: Divide the batter evenly among the 12 cups. They should be nearly full.
For a bakery-style top, sprinkle a pinch of turbinado sugar on each muffin (optional).
Bake: Place on the middle rack and bake for 16–20 minutes, until the tops are set and lightly golden. A toothpick should come out mostly clean with a crumb or two.
Cool: Let the muffins rest in the pan for 5 minutes. Transfer to a wire rack to cool completely.
This helps them set and keeps the bottoms from getting soggy.
Serve: Enjoy warm or at room temperature. They’re great plain, with a smear of almond butter, or a light drizzle of honey.