Preheat the oven to 375°F (190°C). Line a muffin tin with cupcake liners or grease it with nonstick spray.

In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

In a large bowl, combine the cottage cheese, eggs, sugar, vanilla extract, and melted butter. Whisk until smooth.

Gradually add the dry ingredients to the wet mixture, stirring gently until just combined.

Carefully fold in the blueberries and lemon zest (if using) to avoid overmixing.

Use an ice cream scoop or spoon to evenly divide the batter into the prepared muffin tin. Fill each cup about 3/4 full.

Bake for 18-22 minutes or until a toothpick inserted into the center comes out clean.

Let the muffins cool in the tin for 5 minutes before transferring them to a wire rack.