1. Preheat Oven and Prepare Muffin Pan: Start by preheating your oven to 375 F (190 C). Line a 12-cup muffin pan with paper liners or grease it thoroughly with non-stick spray. This ensures your muffins won’t stick and makes for easy cleanup.

2. Combine Dry Ingredients: In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt. Make sure there are no lumps and the ingredients are evenly distributed. This step is crucial for an even rise.

3. Mix Wet Ingredients: In a separate medium bowl, lightly beat the large egg. Then, add the milk, melted butter, and vanilla extract, stirring until well combined. The mixture should look smooth and uniform.

4. Combine Wet and Dry Mixtures: Pour the wet ingredients into the bowl with the dry ingredients. Stir gently with a spoon or spatula until just combined. The batter should still look a little lumpy; do not overmix, as this can lead to tough muffins.

5. Fold in Cottage Cheese and Blueberries: Gently fold in the cottage cheese and blueberries. Be careful not to crush the blueberries, especially if they are fresh. Mix just enough to distribute them throughout the batter.

6. Fill Muffin Cups: Divide the batter evenly among the 12 prepared muffin cups. You can use an ice cream scoop for easy and consistent portioning. Fill each cup about two-thirds full.

7. Bake Until Golden: Bake for 20-25 minutes, or until the tops are golden brown and a wooden skewer or toothpick inserted into the center of a muffin comes out clean. The muffins will also spring back lightly when touched.

8. Cool Before Serving: Remove the muffin pan from the oven and let the muffins cool in the pan for 5 minutes before transferring them to a wire rack to cool completely. This helps prevent them from getting soggy.