Preheat your oven to 375°F (190°C) and line a 12-cup muffin pan with paper liners or lightly grease it.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and sugar until well combined.
In a large bowl, whisk the egg, sugar, Greek yogurt, oil, lemon zest, lemon juice, and vanilla extract until smooth.
Gently fold the dry ingredients into the wet ingredients just until combined; the batter should remain slightly lumpy to ensure tender muffins.
Carefully fold in the blueberries, taking care not to break them, especially if using frozen berries that have been lightly tossed in flour.
Spoon the batter into the muffin cups, filling each about three-quarters full, and sprinkle the optional streusel topping over each muffin if desired.
Bake for 18–22 minutes, or until a toothpick inserted into the center comes out clean. For bakery-style domed tops, you can start baking at 375°F for the first 5 minutes, then reduce the temperature to 350°F for the remainder of the time.
Cool the muffins in the pan for 5 minutes, then transfer them to a wire rack to cool completely and prevent soggy bottoms. Serve warm or at room temperature, optionally spreading butter, cream cheese, or drizzling a light lemon glaze.