Prep the pan and oven: Heat the oven to 375°F (190°C). Line a 12-cup muffin pan with paper liners or grease lightly.

Whisk dry ingredients: In a large bowl, whisk flour, sugar, baking powder, baking soda, salt, and cinnamon (if using).

Blend or mash the cottage cheese: For a smoother crumb, pulse the cottage cheese in a blender or with an immersion blender for 10–15 seconds. If you like tiny curds in the muffins, you can skip this step.

Mix wet ingredients: In a separate bowl, whisk cottage cheese, yogurt, oil, eggs, vanilla, and lemon zest until smooth and creamy.

Combine wet and dry: Pour the wet mixture into the dry ingredients. Stir gently with a spatula until just combined. The batter should be thick and slightly lumpy—don’t overmix.

Fold in blueberries: Toss blueberries with 1 teaspoon of flour (optional, helps prevent sinking), then fold them into the batter with a few gentle strokes.

Portion the batter: Divide evenly among the muffin cups, filling each about 3/4 full. Sprinkle the tops with turbinado sugar if you like a crunchy lid.

Bake: Place the pan on the middle rack and bake for 18–22 minutes, until the tops are golden and a toothpick inserted in the center comes out with a few moist crumbs.

Cool: Let muffins cool in the pan for 5 minutes, then transfer to a rack. They set as they cool, so resist cutting in too early.

Enjoy: Serve warm or at room temperature. They’re especially good with a dab of butter or a swipe of lemon curd.